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New  Methods  of 
Machine-Gun  Fire 

By 

Capt.  Friedrich  v.  Merkatz 
German  Army 


Reprinted  from 
INFANTRY  JOURNAL 


Washington: 

The  United  States  Infantry  Association 
1916 


COPYRIGHT  1916 
U.  S.  INFANTRY  ASSOCIATION 


.- 


.<;'»«*./.; 

*VL2  :•!,/•  ..  . 


INTRODUCTION 

Captain  v.  Merkatz  was  known  before  the  war  as  one  of  the 
most  prominent  machine-gun  experts  of  the  German  Army.  In 
the  present  study,  he  gives  us  the  benefit  of  his  experience  as  a 
commander  of  a  machine-gun  unit  in  the  great  European  war. 

Perhaps  the  principal  value  of  this  study  lies  in  the  clear  analy- 
sis which  it  contains  of  the  various  classes  of  machine-gun  fire, 
their  application,  and  method  of  employment.  We  know  of  no 
other  book  which  has  so  completely  performed  this  service  in 
respect  to  machine-gun  fire. 

A  study  of  this  character  will  not  bear  casual  reading,  but  must 
be  made  the  object  of  thorough  consideration  and  if  possible  an 
application  of  the  principles  discussed  if  the  full  benefit  is  to  be 
derived  from  it. 

One  of  the  most  interesting  features  of  this  translation  is  the 
method  of  regulating  the  extent  of  zone  (or  "deep")  fire  by 
the  use  of  a  graduated  scale  on  the  hand  wheel.  So  far  as  we 
are  aware,  no  consideration  has  ever  been  given  to  this  question 
in  this  country.  While  zone  fire  finds  little  application  at  the 
shorter  ranges  which  are  the  rule  in  the  use  of  machine  guns  in 
trench  warfare,  the  longer  ranges  at  which  they  will  often  be 
used  in  the  war  of  movements  will  make  necessary  some  method 
of  compensating  for  errors  in  range,  'deficient  observation,  varia- 
tions due  to  setting  up  of  mount,  etc.  By  the  method  described, 
a  zone  of  the  depth  required  in  any  given  case  to  compensate 
for  these  factors  can  be  covered  with  almost  absolute  uniformity. 

A  valuable  hint  as  to  the  method  of  training  gun  pointers  is 
contained  on  pages  20  and  21  of  the  text. 

Directors  of  firing  exercises  will  find  valuable  assistance  in  the 
method  of  appraising  the  results  of  machine  gun  described  on 
page  32-34. 

G.  A.  LYNCH,  Captain,  Infantry, 
Editor  of  the  INFANTRY  JOURNAL. 


349088 


New  Methods  of  Machine-Gun  Fire.1 

By  Captain  Friedrich  v.  Merkatz,  German  Army. 

PART  I.     KINDS  OF  FIRE.2 

GENERAL. 

r  I  THE  machine-gun  sheaf  is  produced  when  continuous  fire  is 
\  delivered  from  a  machine  gun.  Its  size  depends  entirely  on 
the  shaking  of  the  sled,  the  vibration  and  heating  of  the 
barrel,  and  variations  in  the  ammunition.  The  machine-gun  sheaf 
has,  therefore,  constant  dimensions  even  under  service  conditions. 
The  gun  pointer  is  only  able  to  displace  the  sheaf  but  not  to 
enlarge  it.  In  this  lies  the  material  difference  between  the  ma- 
chine-gun sheaf  and  the  infantry  sheaf.  The  sheaf  of  a  poorly 
trained  infantry  company  is  even  in  peace  greater  than  that  of  a 
well-trained  one.  While  under  the  disintegrating  influences  of 
battle,  the  infantry  sheaf  is  materially  enlarged,  that  of  the 
machine  gun  will  even  in  action  deviate  little  or  not  at  all  from 
its  peace  dimensions.  The  so-called  loss  of  nerve  control  does  not 
appear  here  to  the  same  extent,  because  being  protected  by  the 
cover  of  the  gun  and  in  some  cases  by  the  shield,  etc.,  the  gun 
pointer  is  not  subjected  to  the  same  extent  to  the  influences  of 
battle.  With  100  or  200  m.  deep  fire,  the  new  method  of  firing 
is  so  coarse  that  even  any  loss  of  nerve  control  which  results  in 
displacement  of  the  sheaf  through  aiming  errors,  but  as  just 
stated,  not  in  an  enlargement  of  the  sheaf,  would  be  neutralized. 
The  commander  has  it  in  his  hands  to  adapt  the  extent  of  deep 
fire  to  service  conditions. 

CHAPTER    1.       SERIES    FIRE. 

Series  fire  is  a  string  of  about  50  shots,  fired  with  fixed  deflec- 
tion and  elevation  levers. 

1  Translated  for  the  INFANTRY  JOURNAL  from  Das  neue  Maschinen-Gewehr 
Schiess-  Verfahren. 

2  The  classification  of  machine-gun  fire  according  to  the  form  of  the  sheaf 
as  given  in  the  original  text  includes:  point  fire  (Punktfeuer) ,  deep  fire  (Tiefen- 
feuer)  and  broad  fire  (Breitenfeuer) .     Although  these    classes  of  fire  roughly 
correspond  to  the  terms  concentrated  fire,  zone  fire,  and  traversed  fire  respec- 
tively, they  are  more  comprehensive  and  are  used  in  certain  cases  where  the 
more  usual  English  term  would  not  apply.     They  have  therefore  been  retained 
throughout  this  translation. — Editor. 


4 


Machine-Gun   Fire 


Figure  1  presents  a  diagram  of  hits  thus  fired  which  was  de- 
scribed on  a  large  target  at  a  range  of  1,000  meters.  The  distribu- 
tion of  the  hits  is  not  the  same  in  every  diagram  of  this  kind,  but 
varies  with  the  vibration  of  the  sled,  quality  of  the  barrel,  etc. 


Series  fire. 
Fifty  shots  with  fixed  deflection  and 
elevation  levers. 
Distance:  1000  m. 

Total  hits  in 
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of  30  cm. 
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FIGURE  1. 


As  may  be  seen  from  Figure  1,  in  series  fire  the  machine-gun  sheaf 
is  very  narrow;  leaving  out  of  consideration  the  isolated  hits  at 
the  extreme  right  and  left,  one  can  speak  here,  e.  g.,  of  a  sheaf 
1  meter  wide  at  1,000  meters.  The  sheaf  is  not  as  narrow  as  this 


Machine-Gun   Fire 


on  all  targets,  and  occasionally  the  width  of  the  sheaf  is  greater 
than  the  height.  These  are  peculiarities  which  have  their  origin 
in  the  construction  of  the  sled  and  the  way  it  is  set  up.  It  is  not 
practicable  to  hit  a  narrow  service  target  with  this  sheaf  on  ac- 
count of  the  limited  facilities  for  observation  under  war  condi- 
tions ;  the  series-fire  sheaf  can  therefore  be  used  only  for  adjust- 
ment fire.  Two  machine  guns  with  the  same  range  will  seldom 
have  the  same  center  of  impact ;  the  location  of  their  sheaves  will 
always  be  somewhat  different  vertically  as  well  as  laterally.  If 
it  is  desired  to  adjust  the  fire  by  platoon,  i.  e.,  to  fire  with  2  or  3 
machine  guns  at  one  and  the  same  point  from  which  the  two 
or  three  sheaves  will  practically  become  one,  the  point  of  aim 
must  be  accurately  announced  and  then  accurate  lateral  adjust- 
ments made.  The  peculiarities  of  the  different  guns  must  be 
reckoned  with,  e.  g.,  a  gun  which  shoots  to  the  left  must  shift 
its  aiming  point,  in  adjustment  fire  by  platoon,  more  to  the  right. 
Differences  in  the  point  of  impact,  which  have  their  cause  in  the 
way  the  sled  is  set  up,  can  in  some  measure  be  counteracted  only 
by  specially  careful  and  uniform  setting  up  of  the  sled  on  its  four 
feet.  In  general,  in  adjustment  fire,  one  must  seek  to  have 
the  sheaves  strike  at  a  lateral  interval  of  5-10  meters  at  the  target 
to  enable  the  platoon  leader,  while  observing,  to  bring  at  least  two 
or  in  platoons  of  three  guns,  all  three  sheaves  if  possible  within 
the  field  of  vision  of  his  glasses.  The  poorer  the  conditions  for 
observation,  the  more  accurately  must  the  point  of  aim  be  de- 
scribed laterally  should  it  be  desired  to  unite  the  sheaves  of  the 
different  machine  guns  into  one. 

In  firing  for  adjustment  on  one  point  with  three  or  six  machine 
guns,  the  sheaves  will  always  so  overlap  that  one  great  sheaf  is 
formed.  This  sheaf  is,  however,  so  deep  that  it  will  give  only 
an  approximate  indication  of  the  range. 

The  depths  of  the  beaten  zone  can  be  found  in  the  table  on 
page  33. 

As  to  the  value  of  these  figures,  there  will  be,  as  always  and 
everywhere,  very  different  views,  but  I  desire  to  point  out  that 
for  practical  shooting,  approximate  knowledge  of  these  figures 
or  better  still,  a  consultation  of  these  tables,  may  save  an  officer 
from  a  false  judgment.  Who,  for  example,  has  not  observed  in 
adjustment  fire  one  or  the  other  sheaf  extraordinarily  deep  ?  And. 


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Machine-Gun   Fire 


shows  a  diagram  fired  with  250  shots  under  service  conditions, 
and  with  loose  deflection  and  elevation  levers.  With  poorly 
trained  gun  pointers  or  slightly  visible  targets,  the  sheaf  is  con- 
siderably widened.  This  sheaf  can  be  narrowed  only  by  having 
the  armorer  sergeant  fit  the  clamping  piece  very  tightly,  or  by 
winding  a  little  asbestos  string  around  the  upper  trunnion  of  the 
jacket  before  screwing  on  the  upper  part  of  the  jacket  carrier, 
so  that  a  lateral  movement  of  the  machine  gun  on  the  cradle  will 
be  impossible.  This  is,  however,  an  obstacle  in  broad  (traversed) 
fire,  and  one  must,  therefore,  be  satisfied  with  a  middle  course. 
The  sheaf  may  also  be  narrowed  with  clearly  visible  aiming 
point  and  when  weather  conditions  most  completely  prevent  the 
appearance  of  powder  smoke.  Should  more  smoke  or  even 
steam  leaking  through  between  barrel  and  stuffing  box  appear,3 
unavoidable  stops  must  be  made  for  resighting.  A  series  fire  is 
the  result. 

Figure  3  is  fired  without  any  deep  fire  with  250  shots,  and 
the  machine-gun  target  is  inserted  correct  to  scale.  From  this  it 
will  be  seen  that  at  1000  meters  even  with  very  good  location  of 
the  sheaf,  one  cannot  always  count  on  a  particularly  high  result. 
Five  or  six  hits  out  of  250  shots,  with  best  location  of  the  sheaf 
and  without  deep  fire,  may  be  regarded  as  a  good  result;  to  prove 
this,  the  target  may  be  placed  in  any  desired  position  in  the  sheaf. 

In  using  deep  fire,  the  sheaf  becomes  thinner,  the  resulting  hits 
therefore  still  fewer.  To  obtain  an  equally  large  number  of 
hits,  the  amount  of  ammunition  must  be  materially  increased. 
From  this  it  follows  that  no  blame  can  be  attached  to  the  gun 
commander  or  gun  pointer  should  his  machine  gun  using  deep 
fire  make  only  1  or  2  hits  out  of  250  shots,  especially  when  at  the 
time  of  firing  the  observation  was  not  good.  Broad  fire  against 
narrow  targets,  which  is  an  intentional  broadening  of  the  already 
really  broad  sheaf  of  point  fire,  is  only  justified  in  very  exceptional 
cases,  with  total  lack  of  observation,  abnormal  weather  condi- 
tions (very  strong  cross  wind),  against  columns  at  long  range, 
etc.  The  result  in  hits  will  in  consequence  be  smaller. 

Point  Fire  as  Fire  for  Eject. 

In  war,  long  lines  of  skirmishers  do  not  always  offer  them- 
selves as  targets,  but  often  only  single  heads  are  visible  which 
3  A  sign  that  the  asbestos  packing  is  too  weak  or  insufficiently  greased. 


10  Machine-Gun   Fire.  , 

do  not  justify  a  long  sustained  fire.  Nevertheless,  these  single 
visible  heads  must  be  fought  down  with  machine  guns.  The 
machine  gun  will,  to  a  certain  degree,  be  on  the  lookout  with 
telescopes,  and  as  soon  as  a  head  appears,  5,  10,  or  even  30  shots 
point  fire  must  cover  the  spot  so  thoroughly  that  no  enemy  will 
venture  again  to  show  his  head  above  his  cover.  These  single 
heads  are  mostly  officers  or  orderlies  and  are  therefore  desirable 
targets.  Point  fire  is  to  be  used  in  fire  for  effect  not  only  against 
single  heads,  but  also  against  long  lines  of  skirmishers  which  are 
not  very  visible.  All  points  where  an  enemy  appears  will  be 
successively  covered  with  point  fire;  one  point  fire  after  another 
will  be  placed  alongside  each  other  after  short  pauses,  so  that 
finally  a  sort  of  broad  fire  results.  Should  the  targets  be  more 
visible,  this  series  of  point  fire  will  become  true  broad  fire.  Deep 
fire  will  here  also  almost  always  be  used.  For  details  see  later 
chapters. 

CHAPTER   3.       BROAD    FIRE. 

(a)  Traversed  Once  Over  the  Target  Without  Deep  Fire. 

Broad  fire  is  delivered  with  loose  deflection  and  elevation 
levers.  It  is  used  in  fighting  against  wide  targets. 

When  changing  to  fire  for  effect,  it  is  every  gun  commander's 
duty  to  again  adjust  his  fire  and  to  try  again  to  secure  observa- 
tion in  his  sector  so  as  to  have  to  use  as  little  deep  fire  as  possible 
in  the  ensuing  fire  for  effect.  If  in  this  repeated  adjustment 
fire  the  gun  commander  attains  his  object — the  sheaf  lay  exactly 
on  the  target — he  changes  to  broad  fire.  One  should  suppose 
in  this  broad  fire  the  sheaf  would  now  remain  in  the  target,  pro- 
vided that  the  target  is  of .  constant  height.  Incontrovertible 
tests  have,  however,  demonstrated  that  in  broad  fire,  the  ma- 
chine-gun sheaf  is  subject  to  variations  which  are  due  to  the 
fact  that  the  four  legs  of  the  sled  are  unevenly  weighted  on  ac- 
•count  of  the  lateral  displacement  of  the  axis  of  the  gun.  Figures 
4,  5,  and  6  show  diagrams  of  hits,  fired  at  battle  ranges  with 
broad  fire,  in  which  the  elevation  aiming  apparatus  was  eliminated. 
The  target  was  simply  covered  with  broad  fire  once.  In  each 
diagram,  sight  was  taken  at  a  point  just  below  the  target  at 
the  beginning  as  well. as  at  the  other  end.  The  diagrams  show 
the  variations  of  the  sheaf  plainly.  An  idea  of  the  extent  of  the 
variations  may  be  readily  formed  when  it  is  known  that  each 


Machine-Gun   Fire  11 

horizontal  strip  is  30  centimeters  high,  and  the  ranges  are  read 
off  from  the  column  on  the  extreme  right.  The  distances  show 
where  the  hits  on  the  target  strike  level  ground.  One  can  easily 
understand  that  these  variations,  as  shown  in  the  diagrams,  are 
not  the  same  in  all  firings.  These  are  characteristic  diagrams 
selected  as  examples  from  a  great  number  of  firings.  They  will 
explain  to  most  machine-gun  officers  what  they  have  often  them- 
selves observed  in  range  firing  without  knowing  the  cause  of  these 
variations;  it  will  make  it  clear  to  them  that  the  gun  commander 
and  gun  pointer  are  often  undeservedly  accused  of  having  fired 
badly.  The  conclusion  in  such  cases  that  the  gun  pointer  de- 
pressed or  raised  the  handle  is  in  most  cases  erroneous;  the  gun 
pointer  cannot  be  held  responsible  for  such  variations  of  the  sheaf 
at  the  target. 

As  we  now  know  the  cause  of  the  variations  of  the  sheaf  at 
the  target,  we  are  in  a  position  to  counteract  these  defects  of  the 
weapon.  These  variations  are  easily  detected  when  firing  under 
excellent  observation,  and  gun  commander  and  gun  pointer  must 
be  so  trained  in  this  respect  that  'they  can  instantly  correct  the 
sheaf  and  hold  it  on  the  target.  It  is  exactly  this  kind  of  firing 
that  occurs  so  often  in  peace,  and  it  forms  an  excellent  school  for 
the  training  of  efficient  gun  commanders  and  gun  pointers. 

Similar  cases  also  occur  under  service  conditions. 

With  less  favorable  observation,  it  often  happens  that  these 
variations  of  the  sheaf  cannot  be  detected  quickly  enough,  and 
the  sheaf  will  often  be  displaced  from  the  target  without  being 
observed  by  the  gun  pointer.  In  such  cases,  the  use  of  deep  fire 
with  broad  fire  is  recommended.  Of  this,  more  will  be  said  later. 

By  closely  scrutinizing  Figures  4,  5,  and  6,  a  good  idea  of  the 
machine-gun  sheaf  in  broad  fire  may  be  formed;  the  sheaf  is  at 
many  points  as  narrow  as  a  thin  band  but  unfortunately  en- 
tirely irregular.  While  the  narrow  places  of  the  fire-swept  zone 
are  often  not  over  10  or  15  meters  deep,  the  broad  parts  of  the 
sheaf  have  often  a  depth  of  from  50  to  100  meters. 

Firing  with  a  narrow  band  seems  often  very  attractive,  but  the 
position  of  the  sheaf  is  too  variable;  such  firing  cannot,  there- 
fore, be  considered  practicable  under  service  conditions  as  a 
habitual  procedure.  This  firing  with  a  narrow  band  not  only 
requires  excellent  conditions  for  observation  at  the  target,  but 


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14  Machine-Gun   Fire 

also  a  location  of  the  target  on  a  rising  slope,  so  that  one  can 
observe  whether  the  sheaf  falls  in  front  of  the  target  or  in  rear. 

The  conditions  for  observation  in  time  of  war  are  identical 
with  those  in  peace:  observation  is  often  excellent,  often  there 
is  none  at  all.  While  before  the  war,  I  was  of  the  opinion  that 
the  machine-gun  sheaf  would  often  disappear  in  the  volume  of 
the  infantry  sheaf  and  of  striking  shrapnel  so  that  it  could  not 
be  observed,  this  was  not  substantiated  in  the  war.  The  machine- 
gun  sheaves  could  generally  be  recognized  even  in  the  most 
intense  firing  of  our  own  troops.  In  battle,  the  difficulty  of  ob- 
servation lies  not  so  much  in  the  visibility  of  the  striking  pro- 
jectiles as  in  the  invisibility  of  the  targets.  This  often  forces 
the  machine  gun  to  use  extensive  deep  fire,  despite  favorable 
conditions  for  observation. 

The  enemy  is  never  in  such  a  position  as  our  targets  in  peace 
have  up  to  the  present  been  located;  instead,  he  lies  behind  the 
rising  ground  and  shows  only  so  much  of  his  head  as  is  absolutely 
necessary  for  firing.  But  firing  with  the  narrow  band  becomes 
nearly  impossible  without  observation  of  the  ground  in  rear  of 
the  target. 

I  would  advise  all  machine  gun  officers  to  endeavor  to  have 
targets  set  up  under  service  conditions ;  although  for  the  training 
of  gun  pointers,  targets  on  a  rising  slope  are  very  instructive. 

Exhaustive  practice  must  be  had  in  firing  against  sections  of 
the  terrain — edges  of  forests,  cuts,  ridges,  etc.  Commanders 
must  be  trained  to  detect  where  the  target  lies;  a  solitary  head 
gives  often  the  only  indication  as  to  its  position.  Commanders 
must  know  how  to  direct  their  machine-gun  fire  against  these 
sections  of  the  terrain,  even  under  the  most  severe  hostile  fire. 
More  detailed  information  is  given  at  the  end  of  Chapter  6  on 
"Tables  of  Fire  Effect." 

(6)  Sustained  Fire  traversed  laterally  back  and  forth  without  deep  fire. 
We  have  seen  in  the  foregoing  chapter  that  the  sheaf  in  broad 
fire  is  very  irregular.  If  the  fire  is  swept  continuously  back  and 
forth  over  the  target  without  deep  fire,  the  irregularities  will 
gradually  adjust  themselves,  and  uniformly  dense  sheaves  will 
result.  These  sheaves,  as  shown,  e.  g.,  in  Figure  7,  could  be  used 
satisfactorily  against  lines  of  skirmishers  had  they  not  several 
faults;  namely:  The  gun  pointer  cannot  change  his  point  of  aim, 


Machine-Gun   Fire  15 

even  when  the  sheaf  falls  in  front  or  in  rear  of  target.  Any  change 
in  the  point  of  aim  causes  a  considerable  enlargement  of  the  sheaf. 
As  may  be  seen  in  the  tables  in  Chapter  5,  this  sheaf  is  very  deep 
in  its  total  extent;  nevertheless,  the  useful  part  of  this  sheaf  is  so 
small  that  a  very  small  error  will  throw  it  off  of  the  target. 
Examine,  e.  g.,  the  sheaf  at  1000  meters.  The  useful  part  is  only 
70  meters  deep.  Should  the  target  lie  well  in  the  useful  part,  a 
variation  of  the  sheaf  of  only  35  meters  would  suffice  to  throw  it 
off  of  the  target.  For  this  reason  the  target  could  not  lie  in 
echelon  as  a  difference  in  range  of  only  35  meters  would  be  sufficient 
to  remove  it  from  the  useful  part. 

In  spite  of  all  this,  some  prefer  to  fire  with  the  last  described 
sheaf,  even  without  observation,  as  in  many  cases  very  high  re- 
sults are  thus  obtained,  needless  to  say,  with  one  uniformly  dis- 
tant target. 

This  is  unquestionably  true,  but  the  effect  is  then  left  to  chance, 
and  it  is  certainly  wrong  for  our  machine-gun  troops  to  be  able 
to  hit  the  target  only  by  chance.  Machine  guns  must  be  able  to 
make  hits — known  hits  at  that — under  service  conditions  even 
without  any  kind  of  observation.  This  was,  until  now,  only 
possible  when  firing  with  several  ranges  and  using  deep  fire. 
The  deep  fire  used  for  this  purpose  was  unsystematic,  as  the 
amount  of  turning  the  handwheel  was  not  uniform. 

(c)  Firing  with  several  sights  without  deep  fire  according  to  the  old 

firing  methods. 

As  will  be  demonstrated  in  a  later  chapter,  we  can  not  depend, 
in  firing  without  observation,  on  the  accuracy  of  the  range  finder 
to  such  an  extent  as  to  use  only  one  sight  setting.  Cases  often 
arise  where  it  becomes  necessary  to  use  2  or  3  sight  settings  with 
100  meters  difference  in  elevation,  or  3  or  5  sights,  with  50  meters 
difference.  With  ranges  of  1000,  1100,  and  1200  meters  for 
example,  we  obtain  Figure  7,  which  was  fired  by  the  gun-proving 
board.  The  amount  of  the  ammunition  used  is  very  great,  the 
sheaves  are  very  large  and  dense;  in  spite  of  this,  the  defect  of  the 
old  method  is  at  once  apparent  in  the  well  defined  high  and  low 
areas  of  hits.  Where  the  target  lies  in  a  high  area,  it  is  full  of 
hits,  'if  in  a  low  area  the  result  to  be  expected  is  zero.  It  must 
also  be  considered  that  this  diagram  was  fired  with  only  one  gun. 


14  Machine-Gun   Fire 

also  a  location  of  the  target  on  a  rising  slope,  so  that  one  can 
observe  whether  the  sheaf  falls  in  front  of  the  target  or  in  rear. 

The  conditions  for  observation  in  time  of  war  are  identical 
with  those  in  peace:  observation  is  often  excellent,  often  there 
is  none  at  all.  While  before  the  war,  I  was  of  the  opinion  that 
the  machine-gun  sheaf  would  often  disappear  in  the  volume  of 
the  infantry  sheaf  and  of  striking  shrapnel  so  that  it  could  not 
be  observed,  this  was  not  substantiated  in  the  war.  The  machine- 
gun  sheaves  could  generally  be  recognized  even  in  the  most 
intense  firing  of  our  own  troops.  In  battle,  the  difficulty  of  ob- 
servation lies  not  so  much  in  the  visibility  of  the  striking  pro- 
jectiles as  in  the  invisibility  of  the  targets.  This  often  forces 
the  machine  gun  to  use  extensive  deep  fire,  despite  favorable 
conditions  for  observation. 

The  enemy  is  never  in  such  a  position  as  our  targets  in  peace 
have  up  to  the  present  been  located;  instead,  he  lies  behind  the 
rising  ground  and  shows  only  so  much  of  his  head  as  is  absolutely 
necessary  for  firing.  But  firing  with  the  narrow  band  becomes 
nearly  impossible  without  observation  of  the  ground  in  rear  of 
the  target. 

I  would  advise  all  machine  gun  officers  to  endeavor  to  have 
targets  set  up  under  service  conditions ;  although  for  the  training 
of  gun  pointers,  targets  on  a  rising  slope  are  very  instructive. 

Exhaustive  practice  must  be  had  in  firing  against  sections  of 
the  terrain — edges  of  forests,  cuts,  ridges,  etc.  Commanders 
must  be  trained  to  detect  where  the  target  lies;  a  solitary  head 
gives  often  the  only  indication  as  to  its  position.  Commanders 
must  know  how  to  direct  their  machine-gun  fire  against  these 
sections  of  the  terrain,  even  under  the  most  severe  hostile  fire. 
More  detailed  information  is  given  at  the  end  of  Chapter  6  on 
"Tables  of  Fire  Effect." 

(b)  Sustained  Fire  traversed  laterally  back  and  forth  without  deep  fire. 
We  have  seen  in  the  foregoing  chapter  that  the  sheaf  in  broad 
fire  is  very  irregular.  If  the  fire  is  swept  continuously  back  and 
forth  over  the  target  without  deep  fire,  the  irregularities  will 
gradually  adjust  themselves,  and  uniformly  dense  sheaves  will 
result.  These  sheaves,  as  shown,  e,  g.,  in  Figure  7,  could  be  used 
satisfactorily  against  lines  of  skirmishers  had  they  not  several 
faults;  namely:  The' gun  pointer  cannot  change  his  point  of  aim, 


Machine-Gun   Fire  15 

even  when  the  sheaf  falls  in  front  or  in  rear  of  target.  Any  change 
in  the  point  of  aim  causes  a  considerable  enlargement  of  the  sheaf. 
As  may  be  seen  in  the  tables  in  Chapter  5,  this  sheaf  is  very  deep 
in  its  total  extent;  nevertheless,  the  useful  part  of  this  sheaf  is  so 
small  that  a  very  small  error  will  throw  it  ofl  of  the  target. 
Examine,  e.  g.,  the  sheaf  at  1000  meters.  The  useful  part  is  only 
70  meters  deep.  Should  the  target  lie  well  in  the  useful  part,  a 
variation  of  the  sheaf  of  only  35  meters  would  suffice  to  throw  it 
off  of  the  target.  For  this  reason  the  target  could  not  lie  in 
echelon  as  a  difference  in  range  of  only  35  meters  would  be  sufficient 
to  remove  it  from  the  useful  part. 

In  spite  of  all  this,  some  prefer  to  fire  with  the  last  described 
sheaf,  even  without  observation,  as  in  many  cases  very  high  re- 
sults are  thus  obtained,  needless  to  say,  with  one  uniformly  dis- 
tant target. 

This  is  unquestionably  true,  but  the  effect  is  then  left  to  chance, 
and  it  is  certainly  wrong  for  our  machine-gun  troops  to  be  able 
to  hit  the  target  only  by  chance.  Machine  guns  must  be  able  to 
make  hits — known  hits  at  that — under  service  conditions  even 
without  any  kind  of  observation.  This  was,  until  now,  only 
possible  when  firing  with  several  ranges  and  using  deep  fire. 
The  deep  fire  used  for  this  purpose  was  unsystematic,  as  the 
amount  of  turning  the  handwheel  was  not  uniform. 

(c)  Firing  with  several  sights  without  deep  fire  according  to  the  old 

firing  methods. 

As  will  be  demonstrated  in  a  later  chapter,  we  can  not  depend, 
in  firing  without  observation,  on  the  accuracy  of  the  range  finder 
to  such  an  extent  as  to  use  only  one  sight  setting.  Cases  often 
arise  where  it  becomes  necessary  to  use  2  or  3  sight  settings  with 
100  meters  difference  in  elevation,  or  3  or  5  sights,  with  50  meters 
difference.  With  ranges  of  1000,  1100,  and  1200  meters  for 
example,  we  obtain  Figure  7,  which  was  fired  by  the  gun-proving 
board.  The  amount  of  the  ammunition  used  is  very  great,  the 
sheaves  are  very  large  and  dense;  in  spite  of  this,  the  defect  of  the 
old  method  is  at  once  apparent  in  the  well  defined  high  and  low 
areas  of  hits.  Where  the  target  lies  in  a  high  area,  it  is  full  of 
hits,  if  in  a  low  area  the  result  to  be  expected  is  zero.  It  must 
also  be  considered  that  this  diagram  was  fired  with  only  one  gun. 


Machine-Gun   Fire  17 

With  2  or  3  guns,  the  sheaves  would  have  an  entirely  different 
position,  as  only  in  rare  instances  will  several  machine  guns  have 
the  same  center  of  impact.  Should  the  gun  using  a  range  of  1100 
be  a  "short  shooting"  gun,  the  sheaves  1000  and  1100  would 
coincide,  and  between  1100  and  1200  a  still  greater  low  area  of 
hits  than  that  obtained  would  result.  There  would  be  still  less 
assurance  of  success. 

A  systematic  distribution  of  hits  could  be  obtained  with  ma- 
chine guns  having  the  same  center  of  impact5  at  all  distances, 
and  several  sight  settings,  50  meters  apart,  were  taken.  Regard- 
less of  the  center  of  impact,  which  is  never  exactly  the  same,  the 
difficulty  of  selecting  the  ranges  is  added.  How  should,  e.  g., 
three  ranges  be  fired  by  a  section  of  two  guns  ?  Or  five  ranges  by 
a  company  at  a  very  wide  target,  head  figures  at  1000  meters  and 
the  width  of  the  target  300  meters?  To  all  the  before  mentioned 
difficulties  must  be  added  those  of  fire  direction,  since  as  many 
machine  guns  as  there  are  sight-settings  to  be  employed  must  be 
concentrated  on  one  sector  of  the  target.  Should  observation 
become  possible  at  any  point  during  the  firing,  a  change  in  sight 
setting  is  nearly  impossible,  as  it  is  not  known  to  which  range  the 
observed  hits  pertain. 

By  using  several  sight -settings  and  the  old  unsystematic  deep 
fire,  an  approximately  uniform  distribution  of  hits  on  the  target 
would  probably  be  possible,  but  the  extent  of  the  deep  fire  would 
continue  to  be  irregular,  the  difficulties  of  range  selection  would 
be  the  same,  advantage  could  not  be  taken  of  observation,  and  low 
areas  of  hits  could,  moreover,  result  from  different  centers  of 
impact. 

CHAPTER   4.       DEEP    FIRE. 

(a)  Deep  Fire  with  graduated  scale. 

To  avoid  the  faults  and  difficulties  of  the  former  method,  one 
elevation  only  was  used  (here  1,200),  instead  of  several  elevations 
as  in  the  last  mentioned  example,  and  the  handwheel  during 
sustained  fire  was  turned  through  an  arc  equivalent  to  the  dif- 
ference between  the  sight  settings  of  1200  and  1000.  The  re- 

5  The  center  of  impact  is  dependent  not  only  on  the  machine  gun,  but  in 
great  measure  on  the  setting  up  of  the  sled.  A  machine  gun  which  gives  a 
good  center  of  impact,  may  give  an  entirely  different  one  if  moved  2  meters 
to  right  or  left. 


Machine-Gun   Fire  19 

suit  of  this  firing  is  shown  in  Figure  8.  The  dimension  of  the 
sheaf  in  depth  is  the  same  as  in  Figure  7,  the  upper  and  lower 
borders  are  equally  uniform,  but  in  contrast  with  Figure  7,  the 
distribution  of  the  hits  over  the  entire  surface  of  the  target  is 
absolutely  uniform.  The  figures  on  the  right  of  the  illustration 
show  the  total  of  hits  in  each  of  the  30  cm. -high  strips.  Neither 
high  nor  low  areas  of  hits  appear.  A  target  will  be  equally  well 
hit  at  all  distances  of  the  useful  part  of  the  sheaf.  To  obtain 
such  a  result,  the  handwheel  must  be  turned  uniformly,  and  the 
required  turn  must  be  made  sufficiently  but  not  too  far.  The  fol- 
lowing error  may  easily  be  made:  the  gun  pointer  turns  by  jerks, 
i.  e, ,  he  pauses  above  and  below  and  moves  the  line  of  sight  quickly 
over  the  center  part.  The  result  is  many  hits  above  and  below, 
and  a  well  defined  low  area  in  the  center.  The  turning  should 
also  not  be  too  slow,  as  with  a  small  ammunition  supply,  the  dis- 
tribution of  hits  would  not  be  sufficiently  uniform. 

To  give  the  gun  pointer  an  approximate  idea  of  how  far  to  turn 
the  handwheel  at  the  different  ranges  in  order  to  displace  the 
sheaves  100  meters  on  the  target,  the  graduated  scale  was  con- 
structed. 

The  lines  on  the  scale  show  the  gun  pointer  how  far  the  hand- 
wheel  must  be  turned.  The  graduation  lines  correspond  each  to 
100  meters  deep  fire.  At  the  longer  ranges,  the  lines  are  longer, 
since  with  increasing  range  the  graduations  on  the  sight  leaf  are 
also  further  apart,  thus  necessitating  greater  turning  of  the 
handwheel. 

Example:  Range  about  1000  m. 

The  machine  gun  is  sighted  with  half  sight  at  a  target  at  950 
m.  Changing  the  sight  then  to  1050,  the  line  of  sight  is  below 
the  target ;  now  turn  the  handwheel  sufficiently  to  again  bring  the 
line  of  sight  on  the  target,  using  half  sight.  The  space  covered 
by  the  handwheel  is  equal  to  the  line  marked  with  the  number 
1000  on  the  graduated  scale. 

To  deliver  200  or  300  m.  deep  fire,  the  handwheel  must  be 
turned  2  or  3  times  the  amount  indicated  by  the  graduation. 

(b)  Instruction  in  use  of  Deep  Fire. 

It  appears  at  first  difficult  to  keep  to  the  limits  indicated  on 
the  graduated  scale  so  that  the  sections  of  the  terrain  under 
fire  are  really  covered  as  intended.  If  one  takes  the  trouble 


20  Machine-Gun   Fire 

to  determine  the  length  of  a  line,  it  will  be  found  that  in  every 
measurement  a  somewhat  different  result  will  be  obtained.  The 
cause  therefor  may  be  found  in  insignificant  errors  in  aiming 
(full  sight,  half  sight,  etc.),  and  in  faulty  service  of  the  gun  at 
the  point  of  lost  motion  of  the  elevating  device,  which  is  always  in 
some  measure  present. 

The  lost  motion  has  no  effect  if  the  machine  gun  has  some  over- 
weight at  the  rear  end.  This  can  best  be  effected,  even  with  a 
clamping  jacket  carrier,  if  the  gun  pointer  exerts  a  slight  down- 
ward pressure  with  the  hand  on  the  handle.  Should  the  gun 
pointer  press  up  on  the  handle  with  his  hand,  the  lost  motion 
must  first  be  taken  up  before  the  wheel  of  the  elevating  mechanism 
will  again  respond. 

The  hand  on  the  handle  must  be  raised  by  the  elevating  mechan- 
ism; this  will  not  result  in  an  appreciable  over-burdening  of  the 
hand  on  the  wheel. 

The  lines  on  the  graduated  scale  represent  averages  values.  It 
is,  therefore,  not  necessary  to  hold  accurately  to  the  length  of 
the  lines.  Should,  e.  g.,  it  be  desired  with  1200  meters  elevation 
to  cover  the  zone  200  meters  lower,  i.  e.,  to  1000  meters,  neither 
the  "1200"  nor  the  "1000"  line  should  be  taken,  but  about  the 
middle  of  both.  If  it  is  desired  to  obtain  an  accurate  measure- 
ment, sight  should  be  taken  at  first  with  the  lower  and  then  with 
the  higher  sight  setting,  and  thus  the  amount  of  rotation  necessary 
determined. 

For  instruction  in  deep  fire,  the  device  for  aiming  control  for 
machine  guns  constructed  by  Captain  Freiensehner  is  eminently 
adapted. 

In  instruction  with  this  device,  a  board  is  placed,  as  shown  in 
the  illustration  (Figure  9),  in  a  frame  under  the  muzzle.  The 
pencil  holder  is  inserted  with  its  upper  end,  the  fork,  under  the 
stuffing-box,  so  that  the  pencil  point  rests  against  the  board. 
The  pencil  has  an  elastic  movement  to  the  front  and  is  held  back 
by  the  instructor  with  a  string,  and  is  only  released  to  record 
control  points  or  control  lines. 

The  following  can  be  accomplished  with  this  apparatus : 

1.  Exercises  in  Adjustment  Fire. 

In  aiming  drill,  with  and  without  blank  ammunition,  the  ma- 
chine gun  is  aimed  by  the  instructor  with  a  certain  sight  setting 


Machine-Gun   Fire  21 

at  an  aiming  point.  The  instructor  then  marks  a  control  point  on 
the  board  with  the  device,  and  then  alters  the  direction  of  the 
gun.  The  gun  pointer  will  then  be  required  to  aim  at  the  same 
point  with  the  same  sight  setting,  the  instructor  giving  the  proper 
commands  as  under  service  conditions.  The  instructor  pulls 
back  the  string;  as  soon  as  the  gun  pointer  calls  "ready,"  the 
instructor  releases  the  string,  and  the  error  made  by  the  gun 
pointer  can  be  seen  on  the  board.  The  device  permits  of  several 
sights  being  taken  by  the  gun  pointer  without  compelling  the  in- 
structor to  go  behind  the  gun  every  time  and  verify  the  correctness 
of  the  aim. 

2.  Eoccercise  in  Fire  for  Effect. 

The  instructor  aims  with  a  certain  sight  setting  at  a  target  (at 
first  located  horizontally),  and  with  the  device  draws  on  the 
board  a  horizontal  line  whose  length  corresponds  to  the  width 
of  the  sector  of  the  target  pertaining  to  the  gun.  He  then  sights 
at  the  same  target  with  100  (200,  300)  m.  less  elevation  and  draws, 
as  before,  a  horizontal  line  on  the  board  and  marks  the  lateral 
limits  of  the  sector  pertaining  to  the  gun  with  vertical  lines.  The 
gun  pointer  now  executes  deep  fire  with  the  range  given  by  the 
instructor.  The  waving  lines  now  formed  on  the  board  should 
connect  the  horizontal  lines  drawn  by  the  instructor,  and  should 
not  go  beyond  the  vertical  lines  on  the  sides.  By  continuous 
observation  of  the  lines  now  formed  on  the  board,  the  instructor 
can  constantly  check  the  gun  pointer  and  thus  instruct  him. 

With  targets  which  are  not  horizontal,  the  instructor  must 
draw  on  the  board  the  control  lines  of  the  two  sights  settings  to 
be  used. 

(c)  Use  of  Deep  Fire. 

To  prevent  possible  misunderstanding,  I  wish  to  make  clear 
at  the  beginning  of  this  discussion  that  the  use  of  deep  fire  does 
not  always  mean  the  covering  of  a  zone  at  least  100  or  200  meters 
deep. 

The  extent  of  the  deep  fire  is  dependent  on : 

1.  Observation. 

2.  Target. 

3.  Range. 

The  difficulties  in  firing  without  any  deep  fire  and  the  objec- 
tions to  it  are  described  in  more  detail  in  Chapter  3.  Should  there 


Machine-Gun   Fire  23 

not  be  such  abnormally  favorable  conditions  of  observation  as 
are  necessary  for  such  firing — which  I  prefer  to  designate  as 
"peace  firing" — the  sheaf  on  the  target  must  be  enlarged. 

There  are  many  intermediate  stages  between  "good  observa- 
tion" and  "lack  of  observation"  which  permit  us  to  get  along 
with  very  little  deep  fire — say  50  meters. 

To  get  a  clear  understanding  of  how  little  the  line  of  sight  moves 
with  50  meters  deep  fire,  it  is  only  necessary  to  lie  behind  a  ma- 
chine gun  and  execute  this  deep  fire  with  800  or  1000  meters 
elevation,  accurately  observing  the  handwheel  and  eliminating  the 
lost  motion.  Deep  fire  of  only  50  meters  requires  so  little  turn- 
ing of  the  handwheel  that  the  majority  of  officers  will  be  as- 
tonished. An  extensive  displacement  of  the  sheaf  on  the  target 
is  not  involved;  the  gun  commander's  corrections  of  "higher"  or 
"lower"  often  result  in  more  turning  of  the  wheel  than  is  here 
the  case.  We  will  take  as  an  example  the  most  favorable  condi- 
tion for  observation  to  show  how  much  50  meters  deep  fire  amounts 
to  at  the  target.  Figure  4,  5  and  6  show  the  sheaf  as  it  appears 
on  the  target.  At  a  range  of  800  meters,  50  meters  deep  fire 
causes  a  rise  and  a  fall  of  only  about  45  cm.  (centimeters!)  each, 
which  can  easily  be  seen  from  the  table  of  ordinates  of  the  trajec- 
tory. (See  Appendix.)  In  firing  at  a  steep  slope,  the  sheaf  is 
actually  neither  elevated  nor  lowered  beyond  the  45  cm.,  and  who 
can,  even  with  the  most  powerful  field  glasses,  recognize  such  a 
small  difference,  or  will  be  able  to  say  "too  much  deep  fire"? 
Transferred  to  level  ground,  these  45  cm.  at  800  meters  distance 
are  changed  in  consequence  of  the  flatness  of  the  trajectory  to 
25  meters  high  or  low.  But  again,  who  can  even  with  the  best 
field  glasses  determine  differences  of  25  meters  at  a  distance  of 
800  meters  on  level  ground? 

Fifty  meters  deep  fire  is  insufficient  to  compensate  for  the  varia- 
tions in  the  machine-gun  sheaf  as  shown  in  Figures  4,  5,  and  6. 
To  fire  with  50  meters  deep  fire,  excellent  observation  must  be 
possible.  Every  machine-gun  commander  must  keep  his  target 
under  constant  observation,  and  must  by  continuous  commands  of 
"higher"  or  "lower,"  strive  to  equalize  the  variations.  The  .50 
meters  deep  fire  only  serves  to  counteract,  to  a  certain  extent, 
the  observer's  errors.  Such  small  differences  in  the  lay  of  the 
sheaf  as  25  meters  in  depth  cannot  be  continually  discerned  and 
corrected  with  the  rapidity  required,  even  with  good  field  glasses. 


24  Machine-Gun   Fire 

The  effect  of  fire  is  materially  increased  through  the  50  meters 
deep  fire.  I  have  demonstrated  through  much  firing  that  the 
gun  commander  often  errs  in  judging  the  sheaf's  position  with 
reference  to  the  target.  He  often  believed  himself  to  be  exactly 
on  the  target  but  was  actually  in  front  or  in  rear  of  it  with  the 
narrow  band.  The  50  meters  deep  fire  permits  the  gun  com- 
mander to  compensate  for  many  of  these  errors;  he  catches  the 
target  with  the  end  of  the  useful  part  when  he  would  otherwise 
shoot  over  it. 

I  freely  admit  exceptions  in  the  case  of  gun  pointers  who  can 
hold  the  target  for  a  time  without  any  deep  fire,  but  this  only 
under  the  most  favorable  conditions.  The  majority  of  all  gun 
commanders  and  gun  pointers  will,  in  firing  without  deep  fire,  get 
on  the  target  only  occasionally,  crossing  the  target  to  a  certain 
extent,  though  not  so  frequently  as  when  using  50  meters  deep 
fire.  By  using  50  meters  deep  fire,  the  average  gun  commander 
is  able  to  bring  his  sheaf  more  frequently  in  the  target,  thus 
obtaining  more  hits. 

A  rule  as  to  how  much  deep  fire  to  use  in  every  case,  cannot  be 
laid  down;  this  depends  on  conditions  obtaining  at  the  time. 

The  conviction  comes  unconsciously  that  with  use  of  100,  200, 
or  even  300  meters  deep  fire,  the  useful  part  of  the  sheaf  will  be- 
come so  thin  that  no  hits  can  be  made.  I  ask,  however,  that  a 
trial  be  made  under  the  following  conditions : 

Target:  head  figures  at  1000  to  1100  meters. 

Observation:  poor  or  none. 

Pointers:  men  perfectly  trained  in  deep  fire. 

Adjustment  fire  starts  as  usual  by  platoon  or  with  all  6  machine 
guns  on  one  point. 

With  no  observation,  the  company  will  be  given  a  common 
range  and  200  meters  deep  fire.  At  the  mid  ranges,  the  reading 
of  the  range  finders  will  be  taken  with  due  allowances  for  weather 
conditions. 

With  poor  observation,  100  meters  deep  fire  will  be  ordered, 
based  on  the  adjustment  fire. 

In  firing  for  effect,  the  gun  commander  and  officers  step  out 
of  the  line  after  instructing  the  gun  pointers  in  the  distribution  of 
fire.  The  gun  pointers  receive  strict  orders  to  disregard  all 
observed  hits  and  to  find  the  target  solely  with  the  announced 
elevation  and  to  execute  their  200  and  300  meters  deep  fire 
uniformly. 


Machine-Gun   Fire  25 

The  main  point  to  be  observed  in  this  firing  is  the  total  disregard 
of  all  observation. 

The  result  obtained  can  be  almost  exactly  predicted  by  use  of 
the  Tables  of  Fire  Effect,  of  which  more  will  be  said  in  a  later 
chapter.  The  accuracy  of  the  fire  is,  to  say  the  least,  astounding 
in  spite  of  the  fact  that  the  entire  procedure  is  based  solely  on  a 
systematic,  uniform  distribution  of  hits  on  the  target.  The 
accuracy  of  fire  is  so  extraordinarily  great  because  the  corrections 
of  the  gun  commanders  are  eliminated,  and  this  brings  me  to  the 
main  point  that  the  gun  commanders,  through  false  corrections, 
often  remove  the  sheaf  from  the  target  instead  of  improving  it. 
I  lay  here  particular  stress  on  the  firing  under  service  conditions 
with  poor  observation. 

This  method  is  particularly  adapted  for  instruction  firing,  and, 
as  a  contrast,  I  recommend  firing  with  gun  and  platoon  leaders 
in  command,  if  possible  without  any  deep  fire  and  with  poor 
observation.  The  result  of  this  last  firing  will  often  be  poorer 
than  that  of  the  demonstration  firing  notwithstanding  the  100  or 
200  meters  deep  fire  of  the  latter.  The  few  instances  in  the 
latter  case — let  us  call  it  "accuracy  fire" — in  which  the  results 
are  materially  better  than  those  of  deep  fire,  are  so  rare  that  they 
cannot  outweigh  the  great  advantage  of  the  certainty  of  effect 
of  deep  fire. 

For  the  demonstration  firing,  it  is  recommended  that  2  or  3 
lines  of  targets  be  set  up  directly  in  rear  of  one  another  (not 
echeloned  laterally)  at  50  meters  interval  instead  of  one  line  of 
head  figures,  to  show  the  certainty  of  the  fire  effect.  In  such  an 
arrangement,  it  must  be  borne  in  mind  that  the  lines  placed 
behind  one  another  must,  of  course,  lie  in  a  horizontal  plane. 

Deep  fire  against  targets  on  uneven  ground. 

In  mountain  warfare,  where  the  enemy  is  more  or  less  equally 
distant  but  not  on  the  same  level,  the  use  of  the  deep  fire  is  of 
the  utmost  importance. 

As  already  mentioned,  at  800  meters  distance  and  50  meters 
deep  fire,  the  increase  of  the  vertical  diameter  of  the  machine- 
gun  sheaf  is  only  90  centimeters.  Should  the  target  rise  or  fall 
to  a  small  extent,  a  resighting  is  necessary,  as  otherwise  the 
target,  despite  the  deep  fire,  would  lie  above  or  below  the  sheaf. 
The  gun  pointer  must  follow  the  target  with  the  sight  with  the 


26 


Machine-Gun    Fire 


utmost  care.  The  deep  fire  will  contribute  materially  toward 
causing  the  machine-gun  sheaf  to  pass  through  the  target  more 
frequently  than  when  the  gun  pointer  fires  without  deep  fire  at 
the  gun  commander's  commands  only. 


PART  II.    FIRE  EFFECT. 

A.  FIRE  EFFECT  UNDER  NORMAL  CONDITIONS. 
CHAPTER  5.      DIMENSIONS  OF  THE  MACHINE-GUN   SHEAF. 

The  table  in  this  chapter  gives  a  resume  of  dimensions  of  the 
beaten  zone  without  deep  fire,  also  with  50,  100,  200,  and  300 
meters  deep  fire.  The  calculations  are  the  results  of  extensive 
firing  by  the  gun-proving  board.  The  figures,  like  all  other 
tables,  only  represent  averages. 

The  figures  in  the  columns  "No  deep  fire"  and  U50  meters 
deep  fire"  are  not  interchangeable  with  Figures  1  and  2,  and  4,  5 
and  6,  respectively.  The  figures  given  in  the  table  are  the  aver- 
ages of  a  great  number  of  firings  without  observation  in  which 
the  average  was  based  on  about  1,000  shots  for  each  firing. 

It  will  be  surprising  how  extraordinarily  great  are  the  depths 
of  the  100  per  cent  sheaf  at  short  ranges,  as  shown  in  the  columns 
for  200  and  300  meters  deep  fire.  This  is  caused  by  the  off- 
shoots in  -the  extremities  of  the  sheaf,  which  actually  occur  with 

TABLE — THE  100  PER  CENT  AND  USEFUL  DEPTHS  OF  THE  BEATEN  ZONES 

IN  METERS. 


Distance  in 
meters 

No  deep  fire 

50  m.  deep  fire 

100  m.  deep  fire 

200  m.  deep  fire 

300  m.  deep  fire 

100 

per  cent 
sheaf 

Useful 
part 

100 

per  cent 
sheaf 

Useful 
part 

100 

per  cent 
sheaf 

Useful 
part 

100 

per  cent 
sheaf 

Useful 
part 

100 

per  cent 
sheaf 

Useful 
part 

800 
900 
1000 
1100 
1200 
1300 
1400 
1500 
1600 

250 
220 
200 
185 
170 
155 
145 
140 
140 

80 
75 
70 
70 
65 
65 
60 
60 
60 

350 
290 
250 
220 
200 
190 
180 
180 
175 

140 
120 
110 
100 
90 
85 
85 
85 
85 

460 
385 
330 
290 
260 
240 
225 
215 
210 

190 
170 
150 
140 
130 
120 
110 
105 
100 

570 
480 
420 
375 
340 
310 
280 
260 
250 

240 
230 
220 
210 
200 
200 
200 
200 
200 

750 
670 
600 
530 
480 
440 
410 
380 
350 

300 
300 
300 
300 
300 
300 
300 
300 
300 

Machine-Gun   Fire  27 

the  coarse  method  of  300  meters  deep  fire  and  the  additional 
errors  of  the  gun  pointers  as  a  result  of  the  flatness  of  the 
trajectory.  These  are  not  merely  calculated  values,  but  were 
obtained  by  actual  firing. 

CHAPTER   6.      TABLES   OF   FIRE   EFFECT.6 

Figure  8  shows  the  even  distribution  of  the  hits  on  a  tar- 
get when  the  gun  pointer  executes  deep  fire  correctly.  By  reason 
of  this  even  distribution,  it  is  possible  to  calculate  the  percentage 
of  direct  hits  to  be  expected  within  the  useful  part,  against 
targets  of  any  size,  with  any  interval. 

Needless  to  say,  ricochets  cannot  be  calculated ;  but  I  must  dis- 
cuss in  more  detail  firing  without  and  with  only  50  meters 
deep  fire. 

In  firing  without,  or  with  only  50  meters  deep  fire,  an  attempt 
is  made  to  hold  the  sheaf  of  Figures  4,  5,  and  6  constantly  on  the 
target  in  accordance  with  the  corrections  of  the  gun  commander. 
An  exact  calculation  of  the  percentage  of  hits  to  be  expected  in 
this  case  is  impossible.  The  figures  uncler  these  two  headings 
are  therefore  based  on  the  average  dimensions  of  the  sheaf  from 
the  table  on  page  175. 

While,  therefore,  the  tables  showing  100,  200,  or  300  meters 
deep  fire  actually  give  the  approximate  percentage  of  direct  hits 
expected  in  round  nurnbers,  it  is  possible  to  exceed  the  given 
values  materially  with  only  50  meters  or  without  any  deep 
fire,  as  the  sheaf  may  be  narrowed  through  the  corrections  of 
the  gun  commander.  If  the  percentages  shown  here  are  not 
obtained,  it  can  be  seen  from  the  table  that  better  results  could 
possibly  have  been  obtained  if  so  many  corrections  had  not  been 
made.  From  the  depths  of  the  useful  sheaves  at  the  target  as 
shown  in  the  table,  it  may  be  seen  that  in  firing  without  any  deep 
fire  (without  corrections  during  firing),  the  useful  part,  e.g.,  at 
1,000  meters,  is  70  meters  deep.  If  we  succeed  in  bringing  the 
target  within  this  space,  the  percentages  shown  will  be  obtained, 
though  it  must  be  considered  that  with  such  small  useful  spaces 
the  percentages  given  are  only  averages.  At  the  edges,  the  result 
will  be  smaller,  and  in  the  center  alone  will  it  be  greater  than 

"See  pages  29  and  30. 


28  Machine-Gun   Fire 

shown  here.  These  are,  however,  such  small  differences  in  range 
that  in  firing  without  deep  fire,  the  result  is  always  a  matter  of 
chance. 

The  more  deep  fire  is  used,  the  flatter  is  the  area7  of  hits  of  the 
useful  space,  i.  e.,  the  useful  space  is  not  so  sharply  separated 
from  the  outer  parts  of  the  sheaf,  the  transition  is  more  gradual, 
and  20  or  even  50  meters  difference  in  range  at  the  target  matters 
little  or  not  at  all,  while  in  firing  without  deep  fire,  even  10  meters 
make  an  enormous  difference  in  the  percentages  of  direct  hits 
expected. 

If  the  result  to  be  expected  is  exceeded,  the  useful  space  has 
been  diminished. 

If  the  result  to  be  expected  is  not  attained,  the  useful  space 
has  been  enlarged.  Should  the  corresponding  deep  fire  have, 
nevertheless,  been  used,  it  was  incorrectly  delivered,  or  the  gun 
commander  did  not  succeed  in  bringing  the  useful  space  into  the 
target.  He  would  probably  have  done  better  in  the  latter  case 
had  he  used  more  deep  fire. 

The  percentages  shown  below  give  only  averages.  The  result 
obtained  will,  however,  always  approximate  the  figures  in  the 
table  though  it  should  again  be  emphasized  that  the  more  deep 
fire  is  used  the  more  closely  will  the  figures  agree. 

The  Tables  of  Fire  Effect  are  naturally  of  no  value  for  use 
in  war,  as  it  would  be  impossible  to  calculate  whether  the  firing 
will  or  will  not  obtain  commensurate  results.  But  in  peace,  com- 
mander and  troops  can  be  tested  with  the  tables  as  to  whether 
or  not  they  know  how  to  use  their  machine  guns  correctly. 

It  seems  almost  impossible  to  construct,  in  peace,  targets  repre- 
senting service  conditions.  Where  will  lines  of  heads  300  meters 
long  offer  themselves  in  war?  and  for  from  3  to  5  minutes? 
These  were  fallacies !  But  it  is,  nevertheless,  advisable  to  fire 
against  such  targets  in  peace  if  the  error  is  not  committed  of  set- 
ting up  the  targets  so  that  they  are  plainly  visible.  On  the  con- 
trary, but  few  points  of  the  enemy's  lines  should  be  discernible, 
exactly  as  the  targets  show  themselves  in  war.  Here  and  there 
an  incautious  head  shows  itself,  or  a  careless  soldier  betrays, 

"I.e.,  in  the  graphical  representation  as  shown  in  the  right-hand  column 
of  Figures  7  and  8. 


Machine-Gun   Fire 


29 


I.    HEAD  TARGETS. 


Distance 
in  m. 

No  deep  fire 

50  m.  deep  fire 

Depth  of 
useful  part 
at  target 
in  m. 

Clear  interval  in  m. 

Depth  of 
useful  part 
at  target 
in  m. 

Clear  interval  in  m. 

0.5 

0.8 

1.0 

1.5 

2.0 

2.5 

3.0 

0.5 

0.8 

1.0 

,.5 

2.0 

2.5 

3.0 

800 
900 
1000 
1100 
1200 
1300 
1400 
1500 
1600 

80 
75 
70 
70 
65 
65 
60 
60 
60 

4.8 
4.0 
3.3 
2.7 
2.2 
1.8 
1.5 
1.2 

,:„ 

3.7 
3.0 
2.5 
2.0 
1.7 
1.4 
1.1 
0.9 
0.7 

3.2 
2.6 
2.2 
1.7 
1.4 
1.1 
0.9 
0.8 
0.6 

2.4 
2.0 
1.6 
1.3 
1.1 
0.9 
0.8 
0.6 
0.5 

1.9 
1.6 
1.3 
1.0 
0.8 
0.7 
0.6 
0.5 

1.6 
1.3 
1.1 
0.9 
0.7 
0.6 
0.5 

1.'] 
0.9 
0.8 
0.7 
0.5 

140 
120 
110 
100 
90 
85 
85 
85 
85 

2.7 
2.5 
2.2 
2.0 
1.8 
1.6 
1.4 
1.2 
1.0 

2.1 
1.9 

1.7 
1.5 
1.3 
1.2 
1.0 
0.9 
0.7 

1.8 
1.6 
1.5 
1.3 
1.1 
1.0 
0.9 
0.8 
0.6 

1.4 
1.3 
1.1 
1.0 
0.9 
0.8 
0.7 
0.6 
).5 

1.1 
1.0 
0.9 
0.8 
0.7 
0.6 
0.5 
0.5 

0.9 

0.8 
0.7 
0.7 
0.6 
0.5 

0.8 
0.7 
0.6 
0.6 
0.5 

:;: 

Distance 
in  m. 

100  m.  deep  fire 

200  m.  deep  fire 

Depth  of 
useful  part 
at  target 

in  m. 

Clear  interval  in  m. 

Depth  of 
useful  part 
at  target 
in  m. 

Clear  interval  in  m. 

0.5 

0  X 

1  0 

1  S 

>  0 

i  S 

T,  0 

0   S 

0  8 

1  0 

1  S 

?  0 

i  S 

3  0 

800 
900 
1000 
1100 
1200 
1300 
1400 
1500 
1600 

190 
170 
150 
140 
130 
120 
110 
105 
100 

1.8 
1.6 
1.5 
1.3 
1.2 
1.0 
0.9 
0.7 
0.6 

1.4 
1.2 
1.1 
1.0 
0.9 
0.8 
0.7 
0.6 
0  S 

1.1 
1.0 
0.9 
0.8 
0.8 
0.7 
0.6 
0.5 

0.9 
0.8 
0.8 
0.7 
0.6 
0.5 

0.7 
0.6 
0.6 
0.5 
0.5 

0.6 
0.5 
0.5 

6.5 

240 
230 
220 
210 
200 
200 
200 
200 
200 

1.6 
1.4 
1.2 
1.0 
0.8 
0.7 
0.6 
0.5 

1.2 
1.0 
0.9 
0.8 
0.6 
0.5 
0.5 

1.0 
0.9 
0.8 
0.7 
0.6 
0.5 

0.8 
0.7 
0.6 
0.5 
0.5 

0.6 
0.5 
0.5 

0.5 

... 

II.  BREAST  TARGET  (Prone  Silhouettes). 


Distance 

in  m. 

No  deep  fire 

50  m.  deep  fire 

Depth  of 
useful  part 
at  target 
in  m. 

Clear  interval  in  m. 

Depth  of 
useful  part 
at  target 
in  m. 

Clear  interval  in  m. 

0   S 

0  8 

1  0 

1  S 

?  0 

?  S 

T,  0 

0.5 

0.8 

1.0 

1.5 

2.0 

2.5 

3.0 

800 
900 
1000 
1100 
1200 
1300 
1400 
1500 
1600 

80 
75 
70 
70 
65 
65 
60 
60 
60 

8.8 
7.2 
5.9 
4   8 

6.6 

5.4 
4.4 
3  6 

5.7 
4.7 
3.8 
3  1 

4.3 
3.5 
2.9 

7  1> 

3.4 
2.8 
2.3 
1  9 

2.9 
2.3 
1.9 
1  6 

2.4 
2.0 
1.6 
1    3 

140 
120 
110 
100 
90 
85 
85 
85 
85 

5.1 
4.5 
4.0 
3.6 
3.2 
2.8 
2.4 
2.1 
1.7 

3.8 
3.4 
3.0 
2.7 
2.4 
2.1 
1.8 
1.6 
1.4 

3.3 
2.9 
2.6 
2.3 
2.0 
1.8 
1.6 
1.4 
1.2 

2.5 
2.2 
2.0 
1.7 
1.5 
1.3 
1.1 
1.0 
0.9 

2.0 
1.8 
1.6 
1.4 
1.2 
1.0 
0.9 
0.8 
0.7 

1.6 
1.4 
1.3 
1.1 
1.0 
0.9 
0.8 
0.7 
0.6 

1.4 
1.3 
1.1 
1.0 
0.9 
0.8 
0.7 
0.6 
0.5 

3.9 

1     T, 

2.9 
?  4 

2.5 
?  1 

1.9 
1  6 

1.5 
1  ? 

1.3 
1  1 

1.1 
0  9 

2.7 
2.2 
1.7 

2.0 
1.7 
1.4 

1.7 
1.4 
1.1 

1.3 
1.1 
0.9 

1.0 
0.8 
0.7 

0.9 
0.7 
0.6 

0.8 
0.6 
0.5 

Distance 
in  m. 

100  m.  deep  fire 

200  m.  deep  fire 

Depth  of 
useful  part 
at  target 
in  m. 

Clear  interval  in  m. 

Depth  of 
useful  part 
at  target 
in  m. 

Clear  interval  in  m. 

0.5 

0.8 

1.0 

1.5 

2.0 

2.5 

3.0 

0.5 

0.8 

1.0 

1.5 

2.0 

2.5 

3.0 

800 
900 
1000 
1100 
1200 
1300 
1400 
1500 
1600 

190 
170 
150 
140 
130 
120 
110 
105 
100 

3.3 
3.0 
2.7 
2.4 
2.2 
1.9 
1.6 
1.4 
1.1 

2.4 
2.2 
2.0 
1.8 
1.6 
1.4 
1.2 
1.0 
0.8 

2.1 
1.9 
1.7 
1.5 
1.3 
1.2 
1.1 
0.9 
0.7 

1.6 
1.4 
1.3 
1.1 
1.0 
0.9 
0.8 
0.6 
0.5 

1.2 
1.1 
1.0 
0.9 
0.8 
0.7 
0.6 
0.5 

1.1 
1.0 
0.9 
0.8 
0.7 
0.6 
0.5 

0.9 
0.8 
0.8 
0.7 
0.6 
0.5 
0.5 

240 
230 
220 
210 
200 
200 
200 
200 
200 

2.7 
2.4 
2.1 
1.8 

11 

1.1 
0.9 
0.7 

2.0 
1.8 
1.6 
1.4 
1.2 
1.0 

l-l 
05 

1.7 
1.5 
1.4 
1.2 
1.0 
0.8 
0.7 
0  S 

1.3 
1.1 
1.0 
0.9 
0.8 
0.6 
0.5 

1.0 
0.9 
0.8 
0.7 
0.6 
0.5 

0.9 
0.8 
0.7 
0.6 
0.5 

0.7 
0.6 
0.6 
0.5 

30 


Machine-Gun   Fire 


III.  KNEELING  TARGETS  (Kneeling  Silhouettes). 


Distance 
in  m. 

50  m.  deep  fire 

100  m.  deep  fire 

Depth  of 
useful  part 
at  target 
in  m. 

Clear  interval  in  m. 

Depth  of 
useful  part 
at  target 
in  m. 

Clear  interval  in  m. 

0.5 

0.8 

1.0 

1.5 

2.0 

2.5 

3.0 

0.5 

0.8 

1.0 

1.5 

2.0 

2.5 

3.0 

800 
900 
1000 
1100 
1200 
1300 
1400 
1500 
1600 

140 
120 
110 
100 
90 
85 
85 
85 
85 

8.4 
7.5 
6.7 
5.9 
5.2 
4.6 
4.0 
3.4 
2.9 

6.4 
5.8 
5.1 
4.5 
4.0 
3.5 
3.1 
2.7 
2.3 

5.6 
5.0 
4.5 
4.0 
3.5 
3.1 
2.7 
2.3 
1.9 

4.2 
3.8 
3.4 
3.0 
2.6 
2.3 
2.0 
1.7 
1.4 

3.4 
3.0 
2.7 
2.4 
2.1 
1.8 
1.6 
1.4 
1.2 

2.8 
2.5 
2.2 
2.0 
1.8 
1.6 
1.4 
1.2 
1.0 

2.4 
2.1 
1.9 
1.7 
1.5 
1.3 
1.2 
1.0 
0.8 

190 
170 
150 
140 
130 
120 
110 
105 
100 

5.4 
4.9 
4.5 
4.0 
3.6 
3.1 
?  7 

4.2 
3.8 
3.4 
3.1 

2.8 
2.4 
?  1 

3.6 
3.3 
3.0 

2.7 
2.4 
2.1 
1  8 

2.7 
2.4 
2.2 
2.0 
1.8 
1.6 

i  ^ 

2.2 
2.0 
1.8 
1.6 
1.4 
1.2 
]  1 

1.8 
1.6 
1.5 
1.4 
1.2 
1.1 

o  o 

1.5 
1.4 
1.3 
1.2 
1.1 
0.9 
0  8 

?   ? 

1  7 

1  S 

\  7 

f>  Q 

0  8 

0  6 

1.8 

1.4 

1.2 

0.9 

0.8 

0.6 

0.5 

Distance 
in  m. 

200  m.  deep  fire 

300  m.  deep  fire 

Depth  of 
useful  part 
at  target 
in  m. 

Clear  interval  in  m. 

Depth  of 
useful  part 
at  target 
in  m. 

Clear  interval  in  m. 

0.5 

0.8 

1.0 

1.5 

2.0 

2.5 

3.0 

0.5 

0.8 

1.0 

1.5 

2.0 

2.5 

3.0 

800 
900 
1000 
1100 
1200 
1300 
1400 
1500 
1600 

240 
230 
200 
210 
200 
200 
200 
200 
200 

4.5 
3.9 
3.4 
2.9 
2.5 
2.1 
1.7 
1.4 
1.1 

3.5 
3.0 
2.6 
2.3 
1.9 
1.6 
1.3 
1.1 
0.9 

3.0 
2.7 
2.4 
1.9 
1.6 
1.4 
1.2 
1.0 
0.8 

2.3 
2.0 
1.7 
1.4 
1.2 
1.1 
0.9 
0.7 
0.6 

1.8 
1.6 
1.4 
1.2 
1.0 
0.9 
0.7 
0.6 
0.5 

1.5 
1.3 
1.1 
1.0 
0.8 
0.7 
0.6 
0.5 

1.3 
1.1 
1.0 
0.8 
0.7 
0.6 
0.5 

300 
300 
300 
300 
300 
300 
300 
300 
300 

3.0 
2.5 
2.2 
1.9 
1.6 
1.4 
1.2 
1.0 
0.8 

2.3 
2.0 
1.7 
1.5 
1.3 
1.1 
0.9 
0.8 
0.6 

2.0 
1.7 
1.5 
1.3 
1.1 
1.0 
0.8 
0.7 
0.5 

1.5 
1.3 
1.2 
1.0 
0.8 
0.7 
0.6 
0.5 

1.2 
1.0 
0.9 
0.8 
0.7 
0.6 
0.5 

1.0 
0.9 
0.8 
0.7 
0.6 
0.5 

0.8 
0.7 
0.6 
0.6 
0.5 

IV.  FIGURE  TARGETS  (Standing  Silhouettes). 


Distance 

in  m. 

•50  m.  deep  fire 

100  m.  deep  fire 

Depth  of 
useful  part 
at  target 
in  m. 

Clear  interval  in  m. 

Depth  of 
useful  part 
at  target 
in  m. 

Clear  interval  in  in. 

0.5 

0.8 

1.0 

1.5 

2.0 

2.5 

3.0 

0.5 

0.8 

1.0 

1.5 

2.0 

2.5 

3.0 

800 
900 
1000 
1100 
1200 
1300 
1400 
1500 
1600 

140 
120 
110 
100 
90 
85 
85 
85 
85 

13.9 
12.4 
11.1 
9.9 
8.7 
7.6 
6.6 
5.7 
4.8 

,0.7 
9.6 
8.5 
7.6 
6.7 
5.9 
5.1 
4.4 
3.7 

9.2 

1:1 

6.6 
5.8 
5.1 
4.4 
3.8 
3.2 

6.9 
6.2 
5.5 
4.9 
4.3 
3.8 
3.3 
2.8 
2.4 

5.5 
4.9 
4.4 
3.9 
3.5 
3.1 
2.7 
2.3 
1.9 

4.6 
4.2 
3.7 
3.3 
2.9 
2.5 
2.2 
1.9 
1.6 

4.0 
3.6 
3.2 
2.8 
2.5 
2.2 
1.9 
1.6 
1.4 

190 
170 
150 
140 
130 
120 
110 
105 
100 

8.9 
8.1 
7.4 
6.6 
5.9 
5   1 
4.4 
3.8 
3.3 

6.9 
6.3 

5.7 
5.1 
4.5 
3  9 
3.4 
2.9 
2.5 

5.9 
5.4 
4.9 
4.4 
3.9 
3  4 
2.9 
2.5 
2.2 

4.4 
4.0 
3.7 
3.3 
2.9 
2  5 
2.2 
1.9 
1.6 

3.6 
3.2 
2.9 
2.6 
2.3 
2  0 
1.7 
1.5 
1.3 

3.0 
2.7 
2.4 
2.2 
1.9 
1  7 
1.5 
1.3 
1.1 

2.5 
2.3 
2.1 
1.9 
1.7 
1  5 
1.3 
1.1 
0.9 

Distance 
in  m. 

200  m.  deep  fire 

300  m.  deep  fire 

Depth  of 
useful  part 
at  target 
in  m. 

Clear  interval  in  m. 

Depth  of 
useful  part 
at  target 
in  m. 

Clear  interval  in  m. 

0.= 

0.8 

1.0 

1.5 

2.0 

2.5 

3.0 

0.5 

0.8 

1.0 

1.5 

2.0 

2.5 

3.0 

800 
900 
1000 
1100 
1200 
1300 
1400 
1500 
1600 

240 
230 
220 
210 
200 
200 
200 
200 
200 

7.5 
6.5 
S   f 

5.8 

5.0 
4  3 

5.0 
4.3 

3  7 

3.7 
3.2 
?  8 

3.0 
2.6 

9  9 

2.5 
2.2 
1.9 
1.6 
1.4 
1.2 
1.0 
0.8 
0.6 

2.1 
1.8 
1.6 
1.4 
1.2 
1.0 
0.8 
0.7 
0.5 

300 
300 
300 
330 
300 
300 
300 
300 
300 

4.9 
4.3 
3.8 
3.3 
2.8 
2.4 
2.0 
1.7 
1.4 

3.8 
3.3 
2.9 
2.5 
2.2 
1.8 
1.5 
1.3 
1.1 

3.3 

2.9 
2.5 
2.1 
1.8 
1.5 
1.3 
1.1 
0.9 

2.5 
2.2 
1.9 
1.6 
1.3 
1.1 
1.0 
0.8 
0.7 

2.0 
1.7 
1.5 
1.3 
1.1 
1.0 

8:? 

0.6 

1.7 
1.5 
1.3 
1.1 
1.0 
0.8 
0.7 
0.6 
0.5 

1.5 
1.3 
1.1 
0.9 
0.8 
0.7 
0.6 
0.5 

4.? 
4.  1 
3.4 
2.5 
2.4 
1.? 

3.7 
3.1 
2.6 
2.2 
1.8 
1.4 

3.2 
2.7 
2.3 
1.9 
1.5 
1.2 

2.4 
2.0 
1.7 
1.4 
1.1 
0.9 

1.9 
1.6 
1.4 
1.2 
1.0 
0.8 

Machine-Gun   Fire  31 

through  a  movement,  the  location  of  the  enemy's  lines — nothing 
more  should  be  seen.  Nevertheless,  the  enemy's  position  is 
densely  and  almost  uniformly  occupied,  and  his  fire  forces  the 
leader  to  counter  action  and  therefore  to  fire  against  invisible 
targets,  against  sections  of  terrain. 

Right  here  the  full  value  of  firing  with  the  graduated  scale 
becomes  apparent:  the  leader  is  enabled  to  cover  the  enemy's 
position  systematically  with  fire.    The  skill  of  the  leader  and  his 
subordinates  shows  here  to  great  advantage,  as  without  it,  failure 
will  be  the  only  result.     But  so  much  the  better;  leaders  of  this 
kind  should  not  be  entrusted  with  machine  guns  in  war. 
How  can  targets  be  set  up  to  simulate  service  conditions  ? 
It  is  not  absolutely  necessary  to  place  a  silhouette  at  every 
spot  where  an  enemy  skirmisher  would  lie ;  it  is  sufficient  if  every 
target  can  be  hit  considering  the  angle  of  fall. 

Should  the  section  of  terrain  be  correctly  searched  with  the 
machine  guns,  the  target  will  receive  the  same  percentage  of  hits 
10  meters  in  front  or  in  rear. 

It  is  of  utmost  importance  to  fire  against  such  targets  in  peace ; 
of  course,  there  are  other  targets,  but  they  do  not  pertain  to  this 
chapter  which  discusses  only  systematic  deep  fire. 

The  Tables  of  Fire  Effect  give  an  actual  illustration  of  what 
the  machine  gun  is  capable  in  similar  cases  under  service  condi- 
tions, and  if  we  assume  the  minimum  requirement  as  0.5  per 
cent  direct  hits,  it  is  easy  to  calculate  whether  or  not  in  any  given 
case  effective  results  can  be  obtained.  The  Tables  of  Fire  Effect 
also  indicate  how  much  ammunition  must  be  expended  to  obtain 
sufficient  effect  at  the  target. 

These  are  not  problems  for  deliberation  during  the  firing,  but 
they  are  preparations  for  firing  which  the  director  must  work  out 
at  home. 
Example : 

The  company  commander  intends  firing  against  nearly  invisible 
head  targets  at  1  meter  interval,  with  200  meters  deep  fire  at 
1,100  meters.  He  wishes  to  find  out  if  it  will  pay  to  use  such 
deep  fire,  and  also  how  much  ammunition  he  must  expend  in 
this  case  to  obtain  a  satisfactory  result. 
Table  I,  Head  Targets,  shows : 

With  200  meters  deep  fire,  range  1,100  meters  and  1  meter 
interval  =  0.7  per  cent  direct  hits. 


32  Machine-Gun   Fire 

Should  the  company  commander  consider  about  35  or  40  direct 
hits  a  satisfactory  result,  the  amount  of  the  ammunition  required 
would  be  5,000  to  6,000  rounds,  since— 

0.7  x  5000  A  0.7  x  6000 

-  =  35  and  -  7     —  =  42  direct  hits. 


Adding  thereto  the  ricochets,  the  company  commander  will 
obtain  a  satisfactory  result  with  5,000  rounds. 

The  result  will  be  obtained  in  about  3  minutes,  with  absolute 
certainty. 

CHAPTER    7.      CRITIQUE   OF   THE    RESULTS   OF    MACHINE-GUN    FIRE. 

Critique  of  results  depends  upon  the  conditions  of  observa- 
tion under  which  the  firing  was  held.  The  visibility  of  the  target 
also  plays  an  important  part,  as  is.  evident  from  the  preceding 
chapter.  A  machine-gun  company  which  obtains  many  hits  under 
favorable  observation,  is  by  no  means  better  trained  than  the 
one  which  obtains  •  fewer  hits  under  poor  observation.  To  give  a 
just  critique,  the  amount  of  deep  fire  each  machine  gun  used  must 
be  recorded  during  the  firing.  The  results  which  a  well  trained 
company  should  obtain  can  then  be  quickly  calculated  with  the 
aid  of  the  Tables  of  Fire  Effect.  As  a  machine  gun 
will  only  in  exceptional  cases  retain  the  deep  fire  ordered  at.  the 
beginning  during  the  entire  firing,  but  will  in  most  cases  narrow 
the  sheaf,  an  impartial  observer  with  each  machine  gun  must 
note  about  how  many  shots  were  fired  with  each  kind  of  deep  fire. 

When  this  data  has  been  assembled,  the  calculated  results  com- 
pared with  the  hits  obtained  (direct  hits)  show  whether  the 
company  fired  well  or  poorly.8 

Care  must  be  taken  not  to  be  deceived  by  reports  of  a  deeper 
fire  than  was  really  used.  The  officer  in  charge  can  easily  deter- 
mine this  by  observing  the  turning  of  the  handwheel  from  time 
to  time. 

It  is  the  director's  duty  to  decide  whether  the  amount  of  deep 
fire  used  was  correct,  or  if  more  or  less  deep  fire  would  have 
been  proper. 

8See  examples  on  pages  33  and  34. 


Machine-Gun   Fire 


33 


I    j 

W  d 


I  t 

I  * 

H 

O 


d 

fj 

6  6 

700  shots  with  200  m.  deep  fire  =  (7  .0  X  9)   =  6.3  direct  hits. 

"o 

|| 

3  M 

11 

300  shots  with  100  m.  deep  fire  =  (3  X  1  .  1)   =3.3  direct  hits. 

|l 

as 

100  shots  with  50  m.  deep  fire   =  (1   X  1  .  7)   =  1  .  7  direct  hits. 

d 

"o 

CN 

Number 
shots 

§1 

600  shots  with  200  m.  deep  fire  =  (6.0  X  9)   =  5  .4  direct  hits. 

' 

d 

Q* 

ea 

-2 

100  shots,  with  50  m.  deep  fire  =  (1   X  1  .  7)   =  1  .  7  direct  hits. 

"8 

- 

11 

§§ 

500  shots  with  100  m.  deep  fire  =  (5  X  l  •  !)   =  5  -5  direct  hits. 

Z 

d 

(U    *-• 



300  shots,  no  deep  fire                  =  (3   X  2  .  5)   =  7  .  5  direct  hits. 

*O 

D  J5 
.00 

I"8 

II 

500  shots  with  50  m.  deep  fire   =  (5   X  1  .  7)    =  8  .  5  direct  hits. 

d 

i* 

11 

500  shots  with  50  m.  deep  fire   =  (5   X  1  .  7)   =  8  .  5  direct  hits. 

•8 

• 

(M 

IH    (0 

"B-i 

3 

10~ 

100  shots,  no  deep  fire                 =  (1   X  2.5)    =2.5  direct  hits. 

d 

|j 

sea 

200  shots  with    50  m.  deep  fire  =  (2  X  1  .  7)   =  3  .4  direct  hits. 
500  shots  with  100  m.  deep  fire  =  (5  X  1  .  1)   =5.5  direct  hits. 

' 

g 

0 

T*! 

3  M 

8§| 

1  00  shots  with  200  m.  deep  fire   =  (I   X0.9)   =  0.9  direct  hits 

Total,  60.  7  direct  hits. 

I 

34 


Machine-Gun   Fire 


1 


d 

ft 

300  m. 
lOOm. 

1.2  direct  hits. 

0 

<c 

.0  "O 

m 

1  .  2  direct  hits. 

6 

!i 

a 

1  .  5  direct  hits. 

•5 

£)  *O 

o 

1C 

CN 

0 

§*  4) 

ea 

0.6  direct  hits. 

jl 

§§ 

1-H    CS 

1  .8  direct  hits. 

d 

a  w 

U3 

a 

^ 

O 

i  —  > 

II 

1 

a 

d 

Q^ 

1 

1  .  5  direct  hits. 

"8 

CM 

o3^2 

o 

1" 

|l 

a 

d 

"8 



1,2  direct  hits. 

Number 
shots 

1 

9  .  0  total  direct 
hits. 

Machine-Gun   Fire  35 

B.    FIRE    EFFECT    UNDER    SPECIAL    SERVICE    CONDITIONS. 

CHAPTER  8.     ERRORS  IN  RANGE  FINDING. 
(Using  the  Hahn  Range  Finder  and  Range  Finder  No.  14.) 
Should   the   distance   to  a   target   be   measured   with   a   well- 
adjusted  Hahn  range  finder,  the  measurement  may  differ  from 
the  correct  distance  about  as  follows : 

Up  to  1000  m.,  2-3%  of  the  distance; 
Up  to  1500  m.,  3-3*/2%  of  the  distance; 
Up  to  2000  m.,  3^-5^%  of  the  distance; 

The  range  finder  14  is  much  more  accurate. 

Should,  e.g.,  the  correct  distance  to  the  target  be  1000  meters, 
the  measurement  may  be  between  970  and  1030  meters.  Inversely, 
the  target  may  lie  between  970  and  1030  m.  when  1000  m.  was 
measured. 

These  errors  in  range  finding  would  be  of  little  consequence 
if  for  every  distance  there  were  a  corresponding  sight  setting. 
The  sight,  however,  permits  only  50  meters  change;  for  the 
intermediate  distances  there  is  but  one  sight  setting  available, 
e.g.,  the  950  meters  sight  setting  is  used  for  all  firing  between  900 
and  950  meters,  and  also  between  920  and  970  meters.  As  these 
distances  are  first  determined  with  the  range  finder  and  are 
therefore  not  exact,  the  errors  in  range  finding  become  of  more 
importance  in  this  connection,  as  the  following  example  will  show  :' 

A  machine  gun  measured  920  meters  as  the  range  to  a  line  of 
head  targets,  and  fired  with  sight  at  950.  The  range-finder  read- 
ing was  3%  over  the  correct  distance,  which  was  893  meters. 

A  second  machine  gun,  107  meters  in  rear,  measured  970  meters 
to  the  same  target,  and  also  sights  at  950  meters.  The  range- 
finder  reading  was  3%  short,  the  correct  distance  being  1000 
meters. 

Both  guns  determined  the  distance  with  a  comparatively  small 
error,  which  may  occur  even  with  new  range  finders.  However, 
should  both  guns  succeed  in  bringing  the  useful  part  of  the 
sheaf  in  the  target,  i.e.,  with  sights  at  950  meters  to  deliver 
effective  fire  at  893  as  well  as  at  1000  meters,  the  sheaf  must 
have  a  depth  of  at  least  107  meters.  The  table  on  page  175  shows, 
however,  that  the  beaten  zone  at  950  meters  is  only  about  70 
meters  deep,  the  remainder  would,  therefore,  have  to  be  supple- 
mented with  deep  fire. 


36  Machine-Gun   Fire 

In  the  hands  of  troops,  the  range  finders  will  often  show  greater 
errors,  and  consequently  greater  differences  between  distance  to 
target  and  sight  setting  will  occur,  on  account  of  which  the  extent 
of  the  supplementary  deep  fire  must  also  be  greater. 

It  is  assumed  here  that  the  range  measurer  does  not  make 
any  error  at  all.  But  even  an  experienced  range  measurer 
obtains  materially  different  results  when  making  several  meas- 
urements to  one  and  the  same  target,  and  the  differences  become 
greater  with  increase  of  the  distance  to  the  target  and  decrease 
in  its  visibility.  Even  the  best  range  finder  cannot  eliminate 
errors  in  measuring  distances,  and  errors  are  the  rule. 

The  new  range  finder  14  is  an  excellent  optical  instrument,  but 
from  the  foregoing  it  is  seen  that  errors  are  also  made  with  it, 
and  the  deep  fire  should  not  be  too  rapidly  narrowed. 

Leaving  out  of  consideration  the  accuracy  of  range-finding, 
weather  conditions  (Chapter  10,  p.  186)  also  influence  the  range 
•of  the  bullet  materially. 

CHAPTER  9.    ERRORS  IN  ESTIMATING  DISTANCE. 

The  determination  of  the  distance  by  estimation  is  much  less 
accurate  than  with  the  range  finder.  Long  years  of  experiment 
have  demonstrated  that  in  general  the  better  half  of  all  estimates 
at  one  object  lie  in  a  space  extending  10%  of  the  distance  in  front 
or  in  rear  of  the  target. 

In  estimating,  e.g.,  to  a  target  1200  meters  distant,  the  better 
half  of  the  estimates  will  lie  between  1080  (=  1200  —  120)  and 
1320  (=  1200  +  120).  •  The  remaining  estimates  will  be  dis- 
tributed over  a  space  four  or  five  times  as  large,  and  therefore  in 
the  above-mentioned  case  may  lie  between  600  and  1800  meters. 

Reversing  the  case  and  selecting  a  definite  sight  setting  corre- 
sponding to  the  estimate,  the  target  will  be  often  at  a  materially 
different  distance.  Even  when  only  considering  the  better  half 
of  all  estimates  in  an  example,  the  unreliability  of  the  procedure 
becomes  very  apparent. 

A  machine  gun  fires  at  a  target  with  sight  set  at  950  meters 
based  on  an  estimate  of  920  meters.  Even  should  this  be  the  esti- 
mate of  the  better  half,  the  correct  distance  could  be  about  840 
meters  (to  1020). 

A  second  machine  gun,  in  rear,  also  fires  at  the  target  with 


Machine-Gun   Fire  37 

sight  at  950  meters  based  on  an  estimate  of  970  meters.  The 
correct  range  could  be  about  (880  to)  1080  meters. 

In  sum,  with  estimates  of  920  and  970  meters,  both  resulting  in 
a  sight  setting  of  950  m.,  the  distance  could  be  between  840  and 
1080  m. 

To  secure  fire  effect  with  certainty,  the  first  machine  gun  would, 
therefore,  be  compelled  to  cover  the  zone  from  840  to  1020,  the 
second  the  zone  from  880  to  1080 — both  with  950  meters  sight 
setting. 

As  there  is  no  actual  certainty  that  the  estimates  were  those  of 
the  better  half,  the  errors  may  be  considerably  greater. 

Observation  in  war  has  substantiated  this  fully,  as  enormous 
errors  have  been  observed  by  the  author,  who  had  the  excellent 
range  finder  No.  14  at  his  disposal,  and  was,  therefore,  enabled  to 
check  the  sight  settings  of  adjacent  organizations.  To  their  great 
discomfiture,  I  was  able  at  one  time,  for  example,  to  prove  that 
a  target  at  1850  meters  was  fired  at  with  sight  at  950  meters; 
another  time  a  target  2000  meters  distant  with  1200  meters  sight ; 
a  third  time  with  the  fixed  sight  at  a  target  at  700  meters ! 

Could  we  ourselves  have  made  a  better  estimate?  I  doubt  it, 
and  he  who  asserts  that  he  would  never  make  such  errors  should 
check  himself  with  range  finder  14 — after  he  has  estimated — 
and  this  in  battle,  under  fire,  when  he  must  decide  on  the  range 
quickly. 

It  is  the  universal  desire  that  every  platoon  commander  be 
provided  with  an  instrument  for  measuring  distance  which  will 
protect  him  at  least  from  excessively  great  errors;  it  is  to  be 
hoped  that  our  optical  industry  will  soon  succeed  in  giving  us 
such  an  instrument,  handy  and  light. 

CHAPTER  10.      INFLUENCES  OF  WEATHER. 

In  its  flight  from  the  muzzle  to  the  target,  the  bullet  is  subject, 
in  addition  to  the  natural  law  of  gravity,  to  the  varying  atmos- 
pheric influences.  The  resistance  the  bullet  encounters  in  its 
flight  is  mainly  dependent  on  the  following : 

(a)  Weight  of  the  air  (Luftgewicht9) . 

(b)  Motion  of  the  air. 

9The  correct  technical  equivalent $  for  the  word  here  used  in  the  German 
text  is  "density  of  the  air."  The  literal  translation  "weight  of  the  air"  is 
here  employed,  as  otherwise  the  explanation  which  follows  would  be 
meaningless. — Editor. 


38 


Machine-Gun   Fire 


(a)  Weight  of  the  Air. 

To  assist  the  officer  who  is  not  familiar  with  such  details,  vari- 
ous points  will  be  more  fully  explained  in  the  following,  which 
to  the  expert  seem  self-evident.  The  expression  "weight  of  the 
air"  does  not  mean  the  air  pressure,  as  read  from  a  barometer,  but 
denotes  the  density  of  the  air — the  mass  the  bullet  must  pene- 
trate in  its  flight.  When  it  is  said  that  the  density  of  the  air  is 
1225,  it  is  meant  that  1  cubic  meter  of  air  weighs  1225  grams. 

TABLE  A. 

Weight  of  a  cubic  meter  of  air  in  grams  with  50  per  cent  humidity  and 
various  barometer  and  thermometer  readings: 


Temperature 


With  a  barometer  reading  of 


in  degrees 
C. 

710 

720 

730 

740 

750 

760 

770 

780 

+30 

1080 

1095 

1110 

1126 

1141 

1156 

1172 

1187 

+25 

1100 

1115 

1131 

1147 

1162 

1177 

1193 

1209 

+20 

1121 

1137 

1152 

1168 

1184 

1200 

1216^ 

JZ32 

+  15 

1142 

1158 

1174 

1190 

1207 

u$u 

*fa9 

1255 

+  10 

1163 

1179 

1196 

1212 

JP* 

1245 

1261 

1278 

+  5 

1185 

1202 

1219 
.^ 

J0£ 

1242 

1268 

1285 

1302 

*  0 

1207 

122^ 

n?4i 

1258 

1275 

1292 

1309 

1326 
1351 

-  5 

\3&f 

1247 

1265 

1282 

1299 

1317 

1334 

-10 

1254 

1271 

1289 

1307 

1324 

1342 

1360 

1378 

-15 

1278 

1296 

1315 

1333 

1351 

1369 

1387 

1405 

-20 

1304 

1322 

1341 

1359 

1377 

1396 

1414 

1432 

The  greater  the  weight  of  the  air,  the  denser  it  is,  and  the 
denser  is  the  mass  the  bullet  has  to  penetrate,  and  low  shooting 
is  the  result.  The  lighter  the  weight,  the  thinner  is  the  air,  and 
the  bullet  has  less  resistance  to  overcome,  and  high  shooting 
results. 

The  density  of  the  air  is  dependent  on : 

1.  The  air  pressure,  indicated  by  the  barometer  reading.  The 
higher  the  barometer  reading,  the  more  compressed  is  the  air,  and 
denser  it  is. 


Machine-Gun    Fire 


39 


2.  The  temperature,  indicated    by    the    thermometer  reading. 
The  higher  the  temperature,  the  more  expanded  and  thinner  is 
the  air.     Here  it  is  to  be  noted  that  with  the  same  air  pressure, 
different  temperatures  may  obtain  and  vice  versa,  and  that  for 
this  reason  both  these  influences  may  enhance  or  neutralize  each 
other. 

3.  The  humidity  of  the  air,  which  is  so  small  as  to  be  imma- 
terial in  practice. 

TABLE  B. 

In  the  following  table  the  preceding  table  is  converted  into  a  form  suitable 
for  practical  use;  the  data  are  of  course  only  approximate: 

At  about  1000'm.  distance,  the  sheaf  is  displaced  in  meters: 


Temperature 


With  a  barometer  reading  of 


in  degrees 

c. 

710 

720 

730 

740 

750 

760 

770 

780 

+30° 

m 
+70 

m 
+60 

m 
+55 

m 
+50 

m 
+40 

m 
+35 

m 
+30 

m 
+20 

+256 

+60 

+  50 

+45 

+40 

+30 

+25 

+  15 

+10 

+  20° 

+50 

+40 

+35 

+30 

+20 

+  10 

ti 

,** 

+  15° 

+40 

+  30 

+25 

+  20 

+10 

A£ 

--5 

-15 

+  10° 

+30 

+  20 

+  15 

^5 

*<# 

st- 

-10 

-20 

-25 

+  5° 

+  20 

+  10 

+  5<S 

«4 

^      ^ 

^0 
+  ( 

^10 

-20 

-30 

-40 

±  0° 

+  10 

>>K10 

-20^ 

-25 

-30 

-40 

-50 

-  5° 

^f 

"-10 

-20 

-30 

-35 

-45 

-55 

-60 

-10° 

-15 

-20 

-30 

-40 

-50 

-60 

-70 

-75 

-15° 

-25 

-35 

-45 

-55 

-65 

-70 

-80 

-90 

-20° 

-40 

-50 

-60 

-65 

-75 

-85 

-95 

-100 

At  a  range  to  the  target  of  about  1500  meters,  the  sheat  is  displaced  about 
twice  these  amounts. 

Our  sights  are  regulated  on  an  air  density  of  1225  grams.  It 
follows  that  with  an  air  density  of  1225  the  bullet  strikes  where 
aimed.  An  air  density  of  1225  grams,  however,  is  not  dependent 
on  either  the  temperature  or  the  air  pressure  alone,  but  the  line 
running  diagonally  through  the  table  shows  when  conditions  are 


40 


Machine-Gun   Fire 


such  that  the  bullet  strikes  where  aimed,  e.g.,  with  — 5°  C.  and 
a  barometer  reading  of  710  or  with  -(-20°  C.  and  a  barometer 
reading  780.  There  only  remains  to  be  ascertained  how  much  the 
range  is  increased  or  decreased.  It  may  be  said  approximately 
that  a  change  in  the  air  density  of  20  grams  changes  the  range: 

at  a  distance  of  1000  m.,  about  10  m. ; 
at  a  distance  of  1500  m.,  about  15-20  m. 

(b)  Motion  of  the  air. 

The  stronger  the  motion  of  the  air,  the  more  the  bullet  will  be 
deflected  in  its  flight.  Head  wind  shortens  the  range,  wind 
obliquely  from  the  rear  lengthens  the  range  and  also  deflects  the 
bullet. 

The  effect  of  the  wind  is  more  difficult  to  estimate  than  the 
influence  of  the  density  of  the  air,  as  its  direction  and  force  not 
only  change  constantly,  .but  also  change  with  the  elevation  above 
the  ground,  and  it  may  assume  an  entirely  different  direction  and 
force  at  a  distance  from  the  firer.  Gusty  winds  not  only  result  in 
displacement  of  the  sheaf,  but  also  in  a  wider  dispersion.  As  a 
basis  for  judging  the  wind  and  its  influence  on  the  range,  the  fol- 
lowing may  be  of  advantage : 


Effec 

t  on 

.Force  of  wind* 

Distance 

Range 

Sheaf,  laterally 

0.5-7  m.  sec  

1000  m. 

Up  to  15  m. 

Up  to    7m. 

Light  —  moderate 

1500  m. 

Up  to  30  m. 

Up  to  15  m. 

8—16  m.  sec 

1000  m. 

Up  to  30  m. 

Up  to  15  m. 

Brisk  —  strong  

.1500  m. 

Up  to  70  m. 

Up  to  40  m. 

*  Judging  the  force  of  the  wind  appears  difficult,  but  is  very  simple  if  powder  smoke  and 
steam  from  the  machine  gun  is  watched,  and,  at  the  same  time,  the  period  of  one  second  fixed. 
Light  dust  or  tobacco  smoke  serve  the  same  purpose. 

These  figures  are  merely  reference  points  and  mark  the 
approximate  limits  within  which  the  displacement  of  the 
sheaf  takes  place.  It  must  be  considered  that  wind  from  the 
right  will  have  less  influence  than  wind  from  the  left,  as  the  drift 
of  the  bullet  counteracts  its  influence.  In  this  connection,  it  is 
to  be  noted  that  on  account  of  the  faulty  setting  up  of  the  sled 
and  the  error  caused  by  its  vibration,  deflection  to  the  left  may 


Machine-Gun   Fire  41 

result  despite  the  drift  to  the  right  and  wind  from  the  left,  as  was 
incontestably  demonstrated  by  the  gun-proving  board,  even  though 
drift  to  the  right  always  results  in  deflection  of  the  bullet  to  the 
right. 

CHAPTER  11.  LOW  SHOOTING  OF  THE  MACHINE  GUN. 

When  a  well  adjusted  machine  gun  fires  series  fire  at  a  target 
and  then  passes  to  sustained  fire,  the  sheaf  of  the  latter  is  often 
shorter  than  that  of  the  former.  The  cause  for  this  is  not  yet 
satisfactorily  explained,  but  this  much  has  been  established  that  in 
fire  for  effect,  a  range  50  meters  higher  than  was  used  in  series 
fire  is  generally  required.  With  some  machine  guns,  the  sheaf 
does  not  fall  at  all,  but  with  others  as  much  as  100  meters.  The 
platoon  and  gun  commanders  must  watch  their  guns  for  this 
tendency  during  field  firing  and  consider  the  observations  made  in 
selecting  the  sight  setting. 

A  further  falling  of  the  sheaf  in  sustained  fire  does  not  occur 
if  there  is  sufficient  water  in  the  jacket.  Should  the  barrel  be  not 
sufficiently  covered  with  water,  about  2  centimeters  deep,  parts 
of  the  barrel  will  be  out  of  the  water  when  it  boils.  This  results, 
e.g.,  at  a  range  of  1000  meters,  in  shortening  the  range  as  much 
as  200  meters.  In  addition,  the  sheaf  in  this  low  shooting  is 
materially  enlarged  and  becomes  so  thin  that  the  result  obtained 
is  out  of  all  proportion  to  the  amount  of  ammunition  used. 

Should  jams  occur  in  a  machine  gun  that  has  previously  worked 
well,  the  fault  lies  in  most  cases  in  the  shortage  of  water  in  the 
jacket.  During  these  jams,  the  dispersion  is  also  much  greater, 
and  at  the  same  time  the  sheaf  falls  considerably. 

It  is  useless  to  shoot  while  there  are  jams,  as  there  can  be  no 
hits.  It  is  better  to  take  time  to  refill  the  water  jacket  at  once  and 
not  fire  until  this  is  done. 

PART  III. 
MACHINE-GUN  FIRE  IN  TACTICAL  UNITS. 

CHAPTER  12.      FIRING  WITH  MACHINE  GUN  OVER  OUR  OWN  TROOPS. 

Should  machine  guns  be  placed  in  the  firing  lines  of  our  own 
troops,  they  are  forced  to  advance  by  rushes  with  the  infantry. 
This  is,  however,  very  difficult  to  execute  on  account  of  the  bulk 
of  the  material  (ammunition,  water),  and  particularly  on  ac- 


42  Machine-Gun   Fire 

count  of  the  necessity  for  an  assured  ammunition  supply.  More- 
over, machine  guns  especially  draw  the  hostile  fire,  thus  exposing 
the  accompanying  infantry  to  heavy  losses.  For  this  reason,  ma- 
chine guns  should,  if  possible,  be  removed  from  the  firing  line, 
and  should  be  posted  so  that  they  can  shoot  over  the  heads  of  our 
troops.  The  enemy  will  thus  be  compelled  to  divide  his  fire  be- 
tween the  machine  guns  and  the  firing  line.  Firing  through  the 
gaps  of  our  own  lines  has  very  seldom  been  practicable  in  service ; 
machine  guns  therefore  always  seek  to  shoot  over  the  heads  of 
their  own  troops. 

Our  own  troops  can  be  fired  over  with  entire  safety  since  the 
sled  with  its  aiming  apparatus  permits  of  the  certain  control  of 
the  machine-gun  sheaf.  In  a  flat  country,  firing  over  the  heads 
of -the  firing  line  is  barred  on  account  of  the  flatness  of  the 
trajectory.  Theoretically,  it  would  be  practicable  to  fire  over  the 
heads  of  our  troops  without  danger  at  the  longer  ranges  on 
account  of  the  height  of  the  trajectory  (see  Appendix),  but  the 
line  of  sight  would  always  be  directed  at  our  own  troops  or  pass 
very  slightly  above  them,  so  that  such  shooting  is  out  of  the 
question. 

One  requirement  is  to  be  able  to  distinguish  friend  and  enemy 
from  the  position  of  the  machine  gun  in  order  to  prevent  mistakes 
in  observing  the  strike  of  the  bullets.  Elevating  the  line  of  sight 
3  meters  over  the  heads  of  our  own  troops  is  sufficient  to  exclude 
the  possibility  of  endangering  them. 

As  shooting  over  our  own  troops  in  a  flat  country,  for  reasons 
stated  above,  is  out  of  the  question,  machine  guns  must  try 
to  secure  commanding  positions.  Such  positions  need  not  be  as 
high  as  those  for  artillery,  but  only  high  enough  to  permit  the 
line  of  sight  to  be  elevated  3  meters  above  our  own  firing  line  as 
above  stated.  For  the  same  reason,  machine  guns  can  shoot  over 
our  troops  when  the  enemy  occupies  a  commanding  position.  A 
commanding  position  on  the  part  of  the  enemy  is  particularly  ad- 
vantageous when  the  slope  in  front  of  his  position  is  very  steep. 
The  steeper  the  slope,  the  longer  can  we  fire  over  our  own  ad- 
vancing troops  without  endangering  them. 

The  closer  our  lines  approach  the  enemy,  the  more  care  must 
our  officers  take  that  they  do  not  come  within  the  sheaves 
of  the  machine  gun.  For  this  reason,  an  approximate  knowledge 


Machine-Gun   Fire 


43 


of  the  vertical  and  horizontal  diameters  of  the  machine-gun 
sheaves  is  necessary.  In  the  following  tables,  the  dimensions 
of  the  sheaf  with  100  meters,  deep  fire  are  shown;  this  is  the 
maximum  deep  fire  permissible  in  firing  over  our  own  troops. 
Depth  of  the  100  per  cent  machine-gun  sheaf  with  100  meters 
deep  fire : 


Distance  in  m. 

Depth  of  the 
sheaf  in  m. 

Distance  in  m. 

Depth  of  the 
sheaf  in  m. 

800 
900 
1000 
1100 

460 
385 
330 
290 

1200 
1300 
1400 
1500 

260 
240 

225 
215 

The  100  per  cent  vertical  diameter  with  100  meters  deep  fire : 


100  per  cent  vertical  diameter  at  a  range  to  the  target  of 

At  3.  distcincc  of  m. 

1000  m. 

1500m. 

100 

1 

1.5 

200 

2 

2.5 

300 

3 

4 

400 

4 

5 

500 

5 

6.5 

600 

6 

8 

700 

7 

9 

800 

8 

10.5 

900 

9 

12 

1000 

10 

13 

1100 

14.5 

1200 

16 

1300 

17 

1400 

18.5 

1500 

20 

When  firing  over  our  own  troops,  the  machine-gun  barrels 
should  not  be  used  above  6,000  rounds.10  The  water  jacket  must 
always  be  full.  Should  the  water  in  the  jacket  be  cool  at  the 
beginning  of  the  firing,  1,000  rounds  can  be  fired  without  inter- 
ruption from  the  same  barrel  without  materially  enlarging  the 
sheaf  or  altering  its  center  of  impact.  Further  firing  requires 
the  refilling  of  the  jacket  after  every  500  rounds.  With  bar- 
rels which  have  been  fired  beyond  these  limits  or  are  insuffi- 
ciently submerged  in  water,  the  beaten  zone  is  at  once  enlarged 
by  several  hundred  meters. 

"'If  the  barrel  has  been  used  for  firing,  and  there  was  too  little  water 
in  the  gun,  the  barrel  can  no  longer  be  used  for  firing  over  our  own 
troops,  and  new. barrels  should  be  placed  in  the  gun  for  such  firing. 


44  Machine-Gun   Fire 

Firing  through  trees,  brush,  or  even  bunches  of  grass  should 
be  absolutely  avoided,  as  the  resulting  ricochets  endanger  our 
troops.  In  firing  over  our  own  troops,  the  machine  gun  must 
be  so  elevated  that  it  will  be  impossible  for  the  bullets  to  graze 
the  vegetation  of  the  foreground. 

The  probability  that  in  cross  fire  bullets  will  strike  each  other 
and  thus  endanger  our  own  troops,  is  so  slight  that  it  cannot 
affect  our  firing  over  them  in  battle. 

Firing  over  our  troops  has  justified  itself  to  a  remarkable 
degree  in  service.  All  prejudices  against  it,  held  in  time  of 
peace,  soon  vanished. 

The  moral  effect  of  firing  over  our  own  firing  lines,  which  it 
was  feared  would  be  demoralizing,  was  on  the  contrary  reas- 
suring and  aroused  the  attacking  spirit,  as  the  men  know  that 
the  enemy  will  be  covered  with  heavy  machine-gun  fire  during 
their  rushes. 

The  author  has  never  observed  any  wounding  of  our  men 
through  firing  over  them,  despite  the  fact  the  required  3  meter 
elevation  of  the  line  of  sight  was  on  several  occasions  not 
available. 

Experiences  in  the  field  have  demonstrated  that  the  division 
of  the  hostile  fire  caused  by  firing  over  our  own  troops  was 
always  very  marked ;  the  losses  were  never  as  great  as  when 
the  enemy  fired  on  the  machine  gun  and  the  firing  line  with  the 
same  sheaf. 

CHAPTER  13.      FIRING  AGAINST  AEROPLANES. 

This  chapter  is  not  based  on  the  report  of  the  gun-proving 
board,  but  represents  only  the  author's  views  on  firing  against 
aerial  targets. 

The  experiences  of  the  war  in  firing  against  aeroplanes  with 
machine  guns  and  infantry  are  so  far  not  very  encouraging. 
What  is  the  cause  of  these  poor  results,  if  these  apparent  failures 
may  be  so  termed? 

In  the  following  discussion,  particular  mistakes  and  rules 
for  firing  will  be  discussed. 

(a)   The  number  of  machine  guns. 

Firing  at  aeroplanes  may  best  be  compared  with  shooting 
at  partridges  in  hunting.  Even  the  non-hunter  knows  that  a 


Machine-Gun   Fire  45 

partridge  is  not  hunted  with  bullets,  but  with  shot.  Why?  Be- 
cause a  rifle  bullet  flies  past  the  mark,  but  a  sheaf  is  formed  of 
the  many  trajectories  of  shot.  The  denser  and  the  larger  the 
sheaf,  the  greater  the  chances  of  hitting  a  partridge.  A  shot 
gun  which  compresses  its  sheaf  in  a  narrow  space,  is  indeed 
dense  but  so  small  and  narrow  that  it  is  easier  to  miss  with  it 
than  with  a  large,  wide  sheaf. 

I  will  compare  the  dimensions  of  these  two  sheaves  with  a 
machine  gun  with  which  100  and  300  meter  deep  fire  is  executed. 
Here  also  the  100  meter  sheaf  is  denser,  the  different  trajectories 
lying  closer  together.  It  is  therefore  better  to  use  300  meters 
deep  fire,  but  the  sheaf  must,  nevertheless,  be  dense,  and  there- 
fore several  machine  guns  are  required.  How  many  ?  The  more, 
rhe  better,  but  all  guns  must  form  one  large,  dense  sheaf,  other- 
wise dispersion  will  naturally  result. 

I  hope  in  this  discussion  to  convert  those  who  so  far  employed 
only  one  or  two  guns.  In  my  opinion,  the  simultaneous  and  uni- 
fied employment  of  at  least  six  machine  guns  is  necessary. 

(b)   Aiming  in  front  of  the  target. 

Aim  must  be  taken  at  a  point  as  many  meters  in  advance  of 
the  target  as  the  target  travels  during  the  time  required  for  the 
bullet  to  reach  it.  If  this  amount  is  exactly  known,  the  required 
amount  of  windage  can  be  taken  on  the  sight,  aim  taken  directly 
at  the  aeroplane,  and  the  target  kept  continuously  in  the  machine- 
gun  .  sheaf.  In  hunting,  such  devices  are  unknown,  and  the 
hunter  must  determine  instantly  how  far  he  has  to  aim  in  front 
of  the  target.  Each  individual  case  is  also  different;  the  target 
is  viewed  sometimes  from  the  side,  at  other  times  straight  from 
the  front,  and  then  again  obliquely  from  the  rear. 

Differing  from  the  shotgun,  the  machine-gun  sheaf  is  con- 
tinuing in  point  of  time ;  necessary  measures  must  therefore  be 
taken  during  the  firing  as  soon  as  the  target  changes  its  direction. 

The  speed  of  the  targets  also  differs,  one  flies  faster,  another 
slower,  but  unfortunately  this  is  not  known,  as  the  distance  is 
too  great  to  determine  it. 

I  am,  therefore,  of  the  opinion,  that  those  who  require  such 
an  accurately  measured  amount  of  aim  in  front  of  the  target, 
and  follow  the  target  with  the  sight,  are  on  the  wrong  track. 


46  Machine-Gun   Fire 

From  our  firing  so  far,  we  can  utilize  to  advantage  against 
aeroplanes  the  many  experiments  which  we  have  made  against 
targets  moving  rapidly  in  a  lateral  direction.  Hundreds  of  times 
we  have  tried  to  follow  the  target,  'but  we  always  reverted  to 
the  practice  of  placing  the  machine-gun  sheaf  a  distance  in  front 
of  the  target,  holding  it  there  and  using  deep  fire  until  the  target 
has  passed  through  it.  The  cause  of  the  fact  that  few  hits 
were  made,  even  with  this  method,  lies  principally  in  the  insuffi- 
cient amount  of  ammunition,  i.e.,  not  enough  machine  guns  were 
used  because,  as  was  said,  "the  target  was  not  worth  it."  A 
second  cause  of  the  failure  is  that  during  the  firing  observation 
becomes  possible  and  the  gun  commander  shifts  or  narrows  the 
sheaf  (which,  though  thin,  is  correctly  placed)  so  much  that 
the  target  just  passes  it. 

In  the  air,  no  observation  is  possible,  and  we  must  there- 
fore employ  a  method  of  dispersion  so  great  that  not  only  will 
the  amount  of  holding  in  front  of  the  target  be  correctly  esti- 
mated, but  also  the  dispersion  in  depth  will  be  so  great  that  the 
target  must  absolutely  pass  through  the  sheaf. 

More  will  be  presently  said  about  aiming  in  front  of  the 
target. 

The  fastest  fliers — and  we  must  reckon  with  this  class — 
attain  a  speed  of  about  150  km.  per  hour.  Such  a  machine, 
therefore,  covers  about  40  meters  in  one  second.  It  is  then 
necessary  to  aim  as  many  times  40  meters  in  front  of  the  target 
as  the  bullet  requires  seconds  to  reach  the  target;  these  factors 
are: 

at  1000  m.  about  2  sec.  =  2  x  40  =  80  m. 
at  1500  m.  "  4  • "  =  4  x  40  =  160  m. 
at  2000  m.  '  "  7  "  =  7  x  40  =  280  m. 

How  is  the  amount  now  determined?  I  have  used  the  follow- 
ing very  simple  method,  not  only  against  air  targets  but  also 
against  any  other  kind: 

Extend  the  right  arm  and  sight  with  one  eye  at  a  target  over 
the  thumb ;  close  the  eye  and  sight  w-ith  the  other  eye ;  a  point 
will  thus  be  obtained  whose  lateral  distance  from  the  target  is 
almost  exactly  100  meters  at  a  distance  of  1000  meters.  Any 
soldier  can  easily  keep  this  measurement  with  the  eye.  Make  the 
trial.  I  have  trained  soldiers  with  flags  set  up  at  lateral  inter- 


Machine-Gun   Fire 


47 


vals,  and  have  always  found  that  they  discovered  the  point 
immediately  when  I  said,  e.g. :  "250  meters  to  the  right  of  the 
lone  tree !" 


65- < 


FIGURE  10. 

If  this   is  not  believed,   the    following    calculations    may    be 
convincing : 

Interpupillary  distance  about  6  cm. ; 

Distance  from  the  eye  to  thumb  about  65  cm.  ; 

We  therefore  have : 

fi5  cm.  =     6  cm. 


1  cm.  =— -  cm. 


100  cm.  = 

100     m.  — 
1000     m.  = 


65 
6  X  160 
65 

9.2  m. 
92  m. 


—  9.2  cm. 


or  about  100  m.,  sufficiently  accurate  for  practical  purposes. 

In  announcing  ranges,  this  measure  of  100  meters  is  the  unit 
of  measure.  It  is  immaterial  whether  the  target  is  800,  1000  or 
1500  meters  distant.  The  command,  "Hold  100  meters  in  front 
of  the  target,"  means  the  interpupillary  distance  projected  over  the 
thumb.  Of  course,  to  avoid  this,  the  command  could  as  well  be: 
"One  width  in  front  of  the  target,"  or  any  other  similar  command. 
With  the  interpupillary  distance  as  the  unit  of  measure,  I 
always  obtain  the  following  results : 

at    100  m.  about    10  m. 

at  1000  m.      "      100  m. 

at  1500  m.      "      150  m. 

at  2000  m.      "      200  m. 


48  Machine-Gun   Fire 

Should  the  flying  target,  therefore,  pass  exactly  at  right  angles 
at  a  range  of  1500  meters,  it  would  be  necessary  to  hold  160  = 
a  little  more  than  one  width,  or  in  practice:11 

"ll/2   width  in   front  of  the  target!" 

I  never  had  any  difficulties  with  this  target  designation,  but 
have   had   many   when   the   command   was :   "  '10'   or   even   '20' 
lengths  of  the  aeroplane  in  front  of  the  target." 

When  the  aiming  point  has  been  found,  there  is  no  difficulty 
in  holding  it  with  the  eye.  Clouds  often  give  a  most  satisfactory 
reference  point. 

The  height  of  the  target  can  also  be  easily  transferred  laterally. 
The  machine  gun  is  then  held  on  the  established  aiming  point 
with  sustained  fire  and  delivers  deep  fire,  described  in  the  next 
section,  until  the  flier  has  about  reached  this  point.  The  process 
is  then  repeated  as  in  the  case  of  objects  moving  rapidly  in  a 
lateral  direction  on  the  ground. 

Wind  from  the  side,  on  which  we  are  so  dependent  in  the 
case  of  targets  on  the  ground,  need  not  be  considered  as  the 
aerial  target  will  be  deflected  by  it  nearly  as  much  as  the  bullet. 

(c)  Deep  Fire. 

From  section  (a),  we  have  already  seen  that  it  is  advantageous 
to  secure  a  large,  wide  sheaf.  Deep  fire  from  1500  to  1200 
meters,  i.e.,  3  lines,  is  recommended.  If  this  is  tested  with  the 
sight  settings,  it  will  be  found  that  it  is  a  very  deep  fire,  but  it 
can  be  easily  executed  with  the  right  hand. 

This  deep  fire  is  always  used  against  aeroplanes,  regardless 
of  whether  the  firing  is  at  800,  1000  or  1500  meters. 

The  sheaf  is  thus  of  constant  dimensions  with  the  following 
vertical  diameters : 

at  500  m.  =  10.4  m. 
at  1000  m.  =  20.9  m. 
at  1500  m.  =  31.2  m. 

The  machine  guns  thus  cover  with  their  sheaves  a  space  which 
aeroplanes  can  hardly  pass. 

They  will  be  unable  to  escape  such  a  great  sheaf  by  rising 
and  descending  (gliding),  because  they  neither  see  nor  hear  it. 

II  See  calculations  on  page  46. 


Machine-Gun   Fire 


49 


FIGURE  11. 

It  is   therefore  only  necessary  to  bring  the  sheaf  in   front  of 
the  target. 

(d)  Distance. 

It  has  been  often  asserted  that  the  distance  to  an  aeroplane 
could  be  estimated  after  some  practice.  I  admire  such  artists, 
but  I  doubt  their  skill,  since — 

1.  Aeroplanes  are  of  different  sizes. 

2.  Aeroplanes    do    not   always   present   their   broad    sides; 

their  length  is  therefore  not  always  shown. 

3.  No   reference  points   for  estimates   exist   in   the  air,   in 

contrast  to  estimating  distance  on  ground. 

It  is  my  opinion  that  the  distance  to  an  aeroplane  can  never 
be  estimated  with  any  degree  of  accuracy  or  certainty. 

As  a  basis  for  firing  against  aeroplanes,  I  consider  that  the 
range  finder  must  be  relied  on  in  addition  to  the  method  already 
described. 

The  speed  of  the  aeroplane  does  not  in  the  least  alter  this. 
Should  the  aeroplane  be  headed  directly  toward  the  machine 
gun,  this  must  be  considered  in  determining  the  range. 

If  no  range  finder  is  available,  or  if  it  is  impossible  to  obtain 


50 


Machine-Gun   Fire 


the  range  to  the  aeroplane,  it  is  much  better  not  to  shoot  at  all, 
as  it  would  be  a  waste  of  ammunition  to  do  so. 

Are  there  indeed  such  great  changes  in  the  distance? 

In  the  next  section,  this  question  will  be  more  fully  discussed, 
but  it  may  here  be  said  that  this  is  only  the  case  when  the  aero- 
planes fly  very  low.  High-flying  targets,  even  when  they  are 
visible  at  80P,  always  present  a  kind  of  a  laterally  moving  target 
at  which  aim  must  always  be  taken  as  much  in  front  as  if  the 
target  were  flying  in  a  lateral  direction. 

(*)  Altitude  Angles. 

Aeroplanes  fly  at  an  altitude  of  at  least  1000  meters  while 
reconnoitering,  but  this  is  an  exceptionally  low  limit.  We  are 
mostly  concerned  with  targets  at  an  altitude  of  from  1500  to 
2000  meters. 

In  examining  Figure  12,  it  is  seen  that  angles  of  10-30°  do  not 
occur  at  all;  they  could  be  considered  only  as  exceptional  cases 
with  which  we  do  not  have  to  reckon. 


tSOOm, 


FIGURE   12. 

A  flying  target  at  an  altitude  of  1000  meters  and  a  distance 
of  1500  meters  flies  at  an  altitude  angle  of  40°.  A  flying 
target  that  flies  at  an  altitude  of  1500  meters  is  directly  above  the 
machine  gun  when  it  is  at  a  distance  of  1500  meters.  We  are 
therefore  concerned  with  targets  which  appear,  in  general,  at 
altitude  angles  of  from  40  to  90°. 


Machine-Gun   Fire  51 

Are  we  able  to  obtain  results  against  a  target  flying  at  such 
altitudes  ? 

If  we  take  the  stand  that  it  is  impossible  for  us  to  do  anything 
against  these  aeroplanes,  and  therefore  as  a  rule  do  not  open 
fire,  they  will  soon  fly  lower,  and  we  shall  have  to  reckon  more 
than  would  otherwise  be  the  case  with  the  well  known  bombs. 
We  must,  therefore,  do  our  best  to  keep  off  the  aeroplane  as  far 
as  we  can  with  our  ammunition. 

I  maintain  that  we  can  have  very  good  results  up  to  1500 
meters,  just  as  against  targets  on  the  ground. 

The  strong  air  currents,  of  which  so  much  is  said,  exist  in 
general  only  when  there  is  also  a  strong  wind  on  the  ground. 
By  observing  the  clouds,,  it  is  easily  seen  whether  or  not  there 
is  a  strong  wind.  In  very  stormy  weather,  the  clouds  generally 
hang  low,  and  the  aeroplanes  are  compelled  to  fly  lower  if  they 
wish  to  observe  anything.  It  all  depends  on  the  ability  to  bring 
the  target  into  a  systematically  laid  and  very  dense  sheaf;  we 
have  then  excellent  prospects  of  hitting  the  flier,  even  at  dis- 
tances of  1500  or  1800  meters,  regardless  of  the  altitude  angle. 

I  would  never  call  such  firing  waste  of  ammunition. 

(/)  Range  Selection — Instruments  for  measuring  angles. 

Everyone  knows  that  in  firing  with  a  great  angle  of  elevation, 
a  lower  sight  setting  than  the  actual  range  must  be  used,  until 
finally  at  an  altitude  angle  of  90°  nearly  point  blank  range 
is  used. 

Several  such  tables  have  been  "calculated,"  but  unfortunately 
none  have  been  actually  "fired."  It  is  not  so  very  simple  to 
place  a  target  at  a  distance  of  1500  meters  at  an  altitude  angle 
of  70°.  Great  elevations  and  short  distances  prove  nothing. 

For  the  present,  we  must  be  satisfied  with  a  calculated  range 
table,  e.g.,  the  one  calculated  by  v.  Burgsdorff.  Should  there 
be  errors  in  the  table,  the  great  deep  fire  will  equalize  them. 

The  table  alone  does  not  answer  the  purpose  of  the  machine 
gun,  we  must  also  add  the  upper  half  of  the  deep  fire.  As,  how- 
ever, we  fire. with  one  and  the  same  sheaf  at  all  distances — from 
1500  to  1200  meters — and  this,  therefore,  represents  a  fixed 
quantity,  I  have  added  half  of  the  angle  of  the  coarse  deep 
fire  to  the  table  of  v.  Burgsdorff.  The  result  is  the  following 
table : 


52 


Machine-Gun   Fire 


RANGE  TABLE  FOR  MACHINE  GUN  FOR  USE  IN  FIRING  AGAINST  FLYING 

TARGETS. 


Range  to  be  announced  atf 

Measured  distances* 

100  per  cent  vertical 
diameterj 

40° 

50° 

60°             70° 

80° 

800m. 

1000 

950 

900 

850 

800 

16.7  m. 

900m. 

1050 

1000 

950 

900 

800 

18.8  m. 

1000  m. 

1150 

1100 

1000 

950 

850 

20.9m. 

1100m. 

1200 

1150 

1050 

1000 

850 

22.9m. 

1200m. 

1300 

1200 

1150 

1000 

900 

25.0m. 

1300  m. 

1350 

1300 

1200 

1050 

950 

27.0m. 

1400  m. 

1450 

1350 

1250 

1150 

950 

29.1  m. 

1500  m. 

1500 

1450 

1350 

1200 

1000 

31.2  m. 

*  Measured,  not  estimated. 

t  Including  the  coarse  deep  fire  of  1500  to  1200  m. 

J  Of  the  large  sheaf  of  the  deep  fire  from  1500  to  1200  m. 

If,  therefore,  it  is  desired,  for  example,  to  fire  with  50°  altitude 
and  1300  meters  measured  distance,  the  command  is  given: 
"Range  1300—3  lines,"  or  with  80°  altitude  and  1400  meters 
distance:  "Range  950—3  lines."12 

It  is  now  only  necessary  to  determine  the  angle  at  which 
the  target  is  viewed.  Until  "angle  finders"  are  available, 
machine-gun  troops  have  to  resort  to  their  own  devices.  A 
simple  piece  of  board  from  which  a  bullet  is  suspended  by  a 
string  is  sufficient.13  The  table  is  pasted  on  the  board. 

The  use  of  the  angle  finder  is  contingent  upon  the  range 
finder;  without  the  latter  the  former  is  valueless. 

(g)  Firing  Without  Deep  Fire. 

Deep  fire  is  not  appropriate  for  firing  against  flying  targets 
which  are  headed  directly  towards  us  and  which  will,  therefore, 
finally  be  directly  over  us ;  broad  fire  must  here  be  used  in  order 
that  the  shots  may  not  pass  by  the  target.  The  extent  of  the 
broad  fire  to  be  used  is  dependent  on  the  deflection  of  the  bullets 
by  the  wind.  To  meet  all  cases,  I  recommend  a  broad  fire  on 
each  side  of  one-half  of  the  eye  and  thumb  measure,  or  in  total, 
an  entire  width.  This  amount  is,  of  course,  very  great,  but  in 
this  way,  it  is  nearly  impossible  for  the  flying  target  to  pass  by 
the  sides  of  the  sheaf. 

I  intentionally  do  not  recommend  to  aim  at  one  side  against 
the  wind,  but  on  both  sides,  as  in  firing  such  great  altitude  angles, 

12On  the  graduated  scale. 

"After  the  fashion  of  an  improvised  clinometer. — Editor. 


Machine-Gun   Fire  53 

errdrs  are  easily  made  and  the  wind  conditions  are  often 
wrongly  estimated.  Here  again  the  old  principle  applies :  "The 
more  machine  guns,  the  better." 

(/?)   Closing  Remarks. 

The  final  objection  of  those  who  do  not  believe  in  the  success 
of  machine  guns  is  the  familiar  statement  that  only  "chance 
shots"  can  hit  an  aeroplane. 

The  term,  "chance  hits,"  sometimes  does  a  good  deal  of  harm. 
One  may  even  maintain  that  every  shot,  not  called  as  a  bull's- 
eye,  is  a  chance  hit.  I  differ.  A  hit  within  a  systematically 
laid  sheaf  is  not  a  chance  hit,  but  is  based  on  calculation.  If  we 
fire  with  a  machine  gun  against  small  targets  at  1000  meters, 
with  sight  set  at  1050  meters  and  1  line  (deep  fire),  it  cannot 
be  called  accident  if  the  enemy  is  hit.  By  accident,  I  under- 
stand when  at  2000  meters,  a  high,  stray  bullet  hits  a  man.  This 
is  a  chance  hit. 

If  we  succeed  in  placing  the  sheaf  correctly  on  the  target,  it 
is  good  luck  when  a  projectile  hits  part  of  the  machine,  or 
even  the  flier  himself,  in  such  a  manner  as  to  put  the  machine 
hors  de  combat.  The  denser  the  sheaf,  the  better  the  prospect 
of  attaining  such  a  result. 

I  have  no  doubt  at  all  that  such  shooting  is  possible  with 
machine  guns.  Of  course,  well-trained  gun  pointers  are  essen- 
tial, but  this  can  be  easily  accomplished  in  a  machine-gun  com- 
pany when  only  one  man  per  gun  need  be  considered,  much  more 
thoroughly  and  easily  than  in  the  infantry. 


54 


Machine-Gun   Fire 


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UNIVERSITY  OF  CALIFORNIA  LIBRARY 
BERKELEY 


THIS  BOOK  IS  DUE  ON   THE  LAST  DATE 
STAMPED  BELOW 

Books  not  returned  on  time  are  subject  to  a  fine  of 
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expiration  of  loan  period. 


SEP  20  1917 
OCT  30  1917 

9  MAY  26  1926 


29*4-9  ft 


REC'D  LD 

MAR  2  5 '65 -KM 


Sfp 


11969 


50w-7,'16 


YC  02970 


UNIVERSITY.9£ CALIFORNIA  LIBRARY 


